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Anti-parasitic effect of vitamin C alone and in combination with benznidazole against <i>Trypanosoma cruzi</i>

21 September 2018 - 9:00pm

by Vanesa Puente, Agostina Demaria, Fernanda M. Frank, Alcira Batlle, Maria Elisa Lombardo

Background

Drugs currently used for the treatment of Chagas’ disease, nifurtimox and benznidazole, have a limited effectiveness and toxic side effects. With the aim of finding new therapeutic approaches, in vitro and in vivo anti-Trypanosoma cruzi activity of vitamin C alone and combined with benznidazole were investigated.

Methodology/Principal findings

The trypanocidal activity on epimastigote and trypomastigote forms was evaluated by counting parasites in a Neubauer chamber after treatment with the compounds. For the amastigote stage, transgenic parasites expressing β-galactosidase were used and quantified by measuring the β-galactosidase activity. The cytotoxicity of compounds was tested on Vero cells. The redox state of the parasite was evaluated by determining the reduced thiol levels (spectrophotometric assay) and the intracellular oxidative state (by flow cytometry). The in vivo trypanocidal activity was evaluated on a murine model of Chagas’ disease. The trypanocidal activity of vitamin C and benznidazole was similar for the three parasite forms. When combining both drugs, vitamin C did not induce any change in the antiparasitic activity of benznidazole on trypomastigotes; however, on mammal cells, vitamin C diminished the cytotoxicity degree of benznidazole. Two mechanisms of action may be postulated for vitamin C: a lethal pro-oxidant effect on the parasite when used alone, and an antioxidant effect, when combined with benznidazole. A similar behavior was observed on infected mice; i.e., parasite counts in infected mice treated with vitamin C were lower than that of the control group. Animals treated with benznidazole presented lower parasitemia levels, as compared with those treated with vitamin C alone. Again, vitamin C did not cause any effect on the antiparasitic profile of benznidazole. Even though a combined treatment was employed, the antioxidant effect of vitamin C on the host was evidenced; a 100% survival was observed and the weight loss occurring during the acute phase of the infection was reduced.

Conclusions/Significance

Based on these results, the combination of vitamin C with benznidazole could be considered as an alternative treatment for Chagas’ disease. These preliminary results encourage further research to improve the treatment of Chagas’ disease.

Spatial distribution of <i>Taenia solium</i> exposure in humans and pigs in the Central Highlands of Vietnam

20 September 2018 - 9:00pm

by Dinh Ng-Nguyen, Rebecca Justine Traub, Van-Anh Thi Nguyen, Kathleen Breen, Mark Anthony Stevenson

Background

Taenia solium, a pork-borne parasitic zoonosis, is the cause of taeniasis and cysticercosis in humans. In Vietnam, poor sanitation, the practice of outdoor defecation and consumption of raw/undercooked pork have been associated with infection/exposure to T. solium in both humans and pigs. The broad-scale geographic distribution of the prevalence of T. solium varies throughout the country with infection restricted to isolated foci in the north and a more sporadic geographic distribution in the Central Highlands and the south. While cross-sectional studies have allowed the broad-scale geographic distribution of T. solium to be described, details of the geographic distribution of T. solium at finer spatial scales have not been described in detail. This study provides a descriptive spatial analysis of T. solium exposure in humans and pigs and T. solium taeniasis in humans within individual households in village communities of Dak Lak in the Central Highlands of Vietnam.

Methodology/Principal findings

We used Ripley’s K-function to describe spatial dependence in T. solium exposure positive and negative human and pig households and T. solium taeniasis exposure positive and negative households in villages within the districts of Buon Don, Krong Nang and M’Drak of Dak Lak province in the Central Highlands of Vietnam. The prevalence of exposure to T. solium in pigs in Dak Lak province was 9 (95% CI 5 to 17) cases per 1000 pigs at risk. The prevalence of exposure to the parasite in humans was somewhat higher at 5 (95% CI 3 to 8) cases per 100 individuals at risk. Spatial aggregations of T. solium exposure-positive pig and human households occurred in some, but not all of the villages in the three study districts. Human exposure-positive households were found to be aggregated within a distance of 200 to 300 m in villages in Krong Nang district compared with distances of up to 1200 m in villages in M’Drak district. Although this study demonstrated the aggregation of households in which either T. solium exposure- or taeniasis-positive individuals were present, we were unable to identify an association between the two due to the very low number of T. solium taeniasis-positive households.

Conclusions

Spatial aggregations of T. solium exposure-positive pig and human households occurred in some, but not all of the villages in the three study districts. We were unable to definitively identify reasons for these findings but speculate that they were due to a combination of demographic, anthropological and micro-environmental factors. To more definitively identify characteristics that increase cysticercosis risk we propose that cross-sectional studies similar in design to that described in this paper should be applied in other provinces of Vietnam.

Detection and distribution of Sca autotransporter protein antigens in diverse isolates of <i>Orientia tsutsugamushi</i>

20 September 2018 - 9:00pm

by Munegowda C. Koralur, Arunachalam Ramaiah, Gregory A. Dasch

Orientia tsutsugamushi (Ots) frequently causes severe scrub typhus infections in the Asia-Pacific region. Korean investigators have demonstrated that Ots encodes five different autotransporter domain (ATD) proteins (ScaA-ScaE). ScaA functions as an adhesin and confers protective immunity in a lethal mouse model of Ots infection. Specific antibodies are detected against ScaA and ScaC in Korean scrub typhus patients. However, there is limited data on the distribution of the Sca protein genes in diverse isolates of Ots. By BLAST analysis with the conserved beta barrel autotransporter domain (ATD) regions of the sca proteins, we discovered a sixth gene scaF among 3 of 10 new partial Ots genome sequences available at NCBI GenBank (Sido, Karp, AFSC7). We designed two to seven specific TaqMan assays to detect the ATD for each of the six sca genes. The TaqMan assays among those for each sca gene which gave the greatest sensitivity and linearity with DNA log dilutions were then used for screening DNAs from Ots isolates grown in L929 mouse cells for sca genes. The sca prevalence survey was performed for all six sca genes with 178 DNAs from isolates from 12 countries. The survey results were confirmed by conventional PCR with primers from conserved regions of the passenger domains (PD) and ATD of the sca proteins. The ATD was highly conserved between the DNAs of different genotypes compared to the sca PD but each TaqMan assay was sca specific. The percentage positivity for 56 kDa and scaA genes in the 178 DNAs using Ha primers was 59.6% and 62.4%, respectively. Our scaA conventional ATD PCR assay was positive in 98.3% but scaA was present in all 178 DNAs (100%) by ATD TaqMan. scaB, scaC, scaD, scaE and scaF were detected in 33.7%, 97.8%, 93.8%, 97.2% and 43.3% isolates by ATD TaqMan, respectively. The ATDs of Ots sca genes are thus sufficiently conserved between different genotypes for molecular assay design. Four sca genes are widely distributed among diverse Ots isolates from diverse geographical areas. scaB and scaF were detected in fewer Ots isolates and absent from some available genome sequences. Whether the utility of the ScaA, ScaC, ScaD, and ScaE antigenic passenger protein domains exceeds that of the mixed 56 kDa type surface antigens of Ots now used in combination diagnostic assays needs to be determined before they can be considered as suitable alternative serological antigens for diagnosis of scrub typhus.

Molecular characterization and phylogenetic analysis of dengue viruses imported into Taiwan during 2011-2016

20 September 2018 - 9:00pm

by Cheng-Fen Yang, Shu-Fen Chang, Tung-Chien Hsu, Chien-Ling Su, Tzy-Chen Wang, Shih-Hung Lin, Su-Lin Yang, Chien-Chou Lin, Pei-Yun Shu

A total of 1,596 laboratory-confirmed imported dengue cases were identified in Taiwan during 2011–2016. Most of the imported cases arrived from Southeast Asia as well as the Indian subcontinent, the Pacific region, Latin America, Australia and Africa. Phylogenetic analyses of the complete envelope protein gene sequences from 784 imported dengue virus (DENV) isolates were conducted, and the results suggest that the DENV-1 genotype I and DENV-2 Cosmopolitan genotype comprise the predominant serotype/genotype of DENV strains circulating in Southeast Asia. The DENV-1 genotype III, DENV-3 genotype III and DENV-4 genotype I and II strains were found to be newly emerging in several Southeast Asian countries. Our results also showed that geographical restrictions of DENV-1 genotype I, DENV-1 genotype III and DENV-2 Cosmopolitan genotype are becoming blurred, indicating the extensive introductions and continuous expansions of DENV strains between nations in Southeast Asia. In this study, we present the geographic distribution and dynamic transmission of DENV strains circulating in Southeast Asian countries. In addition, we demonstrated local dengue epidemics caused by several imported DENV strains in Taiwan during 2011–2016.

Health preparedness plan for dengue detection during the 2020 summer Olympic and Paralympic games in Tokyo

20 September 2018 - 9:00pm

by Naoki Yanagisawa, Koji Wada, John D. Spengler, Ramon Sanchez-Pina

Background

Participants in mass gathering events are at risk of acquiring imported and locally endemic infectious diseases. The 2014 dengue outbreak in Tokyo gathered attention since it was the first time in 70 years for Japan to experience an autochthonous transmission. Preparation for emerging infectious threats is essential even in places where these outbreaks have been largely unknown. The aim of this study is to identify strategies for early detection and prevention of dengue infection during the 2020 summer Olympics and Paralympics in Tokyo.

Methodology/Principal findings

We modified and adapted the failure mode and effect analysis (FMEA) methodology, generally used in industrial manufacturing, to examine the current controls for dengue detection and assessment. Information on existing controls were obtained from publicly available resources. Our analysis revealed that the national infectious disease control system to detect dengue in Japan is robust. However, in the case of large assemblies of international visitors for special events when the spread of communicable and vector-borne diseases increases, there are three main gaps that could be reinforced. First, cyclical training or a certification program on tropical disease management is warranted for physicians, especially those working in non-infectious disease-designated hospitals or clinics. Second, multi-language communication methods need to be strengthened especially in the health and hospitality sector. Third, owners of accommodations should consider incorporating a formal tropical disease-training program for their staff members and have a contingency plan for infectious disease-suspected travelers.

Conclusions/Significance

Our findings may facilitate physicians and public health officials where new controls would be beneficial for the 2020 summer Olympics and Paralympics. The FMEA framework has the potential to be applied to other infectious diseases, not just dengue.

Coinfections and comorbidities in African health systems: At the interface of infectious and noninfectious diseases

20 September 2018 - 9:00pm

by Derick Nii Mensah Osakunor, David Moinina Sengeh, Francisca Mutapi

There is a disease epidemiological transition occurring in Africa, with increasing incidence of noninfectious diseases, superimposed on a health system historically geared more toward the management of communicable diseases. The persistence and sometimes emergence of new pathogens allows for the occurrence of coinfections and comorbidities due to both infectious and noninfectious diseases. There is therefore a need to rethink and restructure African health systems to successfully address this transition. The historical focus of more health resources on infectious diseases requires revision. We hypothesise that the growing burden of noninfectious diseases may be linked directly and indirectly to or further exacerbated by the existence of neglected tropical diseases (NTDs) and other infectious diseases within the population. Herein, we discuss the health burden of coinfections and comorbidities and the challenges to implementing effective and sustainable healthcare in Africa. We also discuss how existing NTD and infectious disease intervention programs in Africa can be leveraged for noninfectious disease intervention. Furthermore, we explore the potential for new technologies—including artificial intelligence and multiplex approaches—for diagnosis and management of chronic diseases for improved health provision in Africa.

Prediction of leprosy in the Chinese population based on a weighted genetic risk score

19 September 2018 - 9:00pm

by Na Wang, Zhenzhen Wang, Chuan Wang, Xi'an Fu, Gongqi Yu, Zhenhua Yue, Tingting Liu, Huimin Zhang, Lulu Li, Mingfei Chen, Honglei Wang, Guiye Niu, Dan Liu, Mingkai Zhang, Yuanyuan Xu, Yan Zhang, Jinghui Li, Zhen Li, Jiabao You, Tongsheng Chu, Furong Li, Dianchang Liu, Hong Liu, Furen Zhang

Genome wide association studies (GWASs) have revealed multiple genetic variants associated with leprosy in the Chinese population. The aim of our study was to utilize the genetic variants to construct a risk prediction model through a weighted genetic risk score (GRS) in a Chinese set and to further assess the performance of the model in identifying higher-risk contact individuals in an independent set. The highest prediction accuracy, with an area under the curve (AUC) of 0.743 (95% confidence interval (CI): 0.729–0.757), was achieved with a GRS encompassing 25 GWAS variants in a discovery set that included 2,144 people affected by leprosy and 2,671 controls. Individuals in the high-risk group, based on genetic factors (GRS > 28.06), have a 24.65 higher odds ratio (OR) for developing leprosy relative to those in the low-risk group (GRS≤18.17). The model was then applied to a validation set consisting of 1,385 people affected by leprosy and 7,541 individuals in contact with leprosy, which yielded a discriminatory ability with an AUC of 0.707 (95% CI: 0.691–0.723). When a GRS cut-off value of 22.38 was selected with the optimal sensitivity and specificity, it was found that 39.31% of high risk contact individuals should be screened in order to detect leprosy in 64.9% of those people affected by leprosy. In summary, we developed and validated a risk model for the prediction of leprosy that showed good discrimination capabilities, which may help physicians in the identification of patients coming into contact with leprosy and are at a higher-risk of developing this condition.

Improved methods to capture the total societal benefits of zoonotic disease control: Demonstrating the cost-effectiveness of an integrated control programme for <i>Taenia solium</i>, soil transmitted helminths and classical swine fever in northern Lao PDR

19 September 2018 - 9:00pm

by Walter O. Okello, Anna L. Okello, Phouth Inthavong, Tassilo Tiemann, Ammaly Phengsivalouk, Brecht Devleesschauwer, Alexandra Shaw, John Allen

Background

Control and elimination of zoonotic diseases requires robust information about their effect on both human and livestock health in order to enable policy formulation and the allocation of resources. This study aimed to evaluate the cost-effectiveness of controlling Taenia solium taeniasis/cysticercosis in both humans and pigs, and soil-transmitted helminths (STH) in humans by integrating their control to on-going human and animal health control programmes in northern Lao People’s Democratic Republic.

Method

A cross-sectional study was carried out in 49 households, focusing on the prevalence of T. solium taenias/cysticercosis and soil transmitted helminths before and after a twelve month intervention. The village data was collected using a semi-structured questionnaire through a door-to-door survey. The village data was then projected to the wider northern Lao PDR population using stochastic modelling and cost-effectiveness ratio (after aggregating the net cost to capture both human and animal health parameters) and GDP per capita as a threshold, to determine the cost-effectiveness of the integrated control of T. solium taeniasis/ cysticercosis and STH, assuming linear scaling out of the intervention. The zoonotic DALY (zDALY) approach was also used as an alternative method of estimating the cost-effectiveness ratio of controlling T. solium taeniasis/cysticercosis in humans and pigs.

Findings

Using cost-effectiveness analysis after aggregating the net cost and control of T. solium taeniasis/cysticercosis alone as the base case, the study found that simultaneous control of T. solium taeniasis/cysticercosis in humans and pigs, STH in humans and Classical Swine Fever (CSF) in pigs was USD 14 per DALY averted and USD 234 per zDALY averted using zDALY method hence considered highly cost-effective whereas controlling T. solium taeniasis/cysticercosis without incorporating STH and CSF was the least cost-effective (USD 3,672 per DALY averted). Additionally, the cost-effectiveness of controlling T. solium taeniasis/cysticercosis in people and pigs using zDALY as an alternative method was USD 3,662 per zDALY averted which was quite close to our findings using the aggregate net cost method.

Conclusion

The study showed that control of T. solium taeniasis/cysticercosis alone in humans and pigs is not cost-effective in northern Lao PDR whereas control of STH is. Consequently, integrating T. solium taeniasis/cysticercosis control with other cost-effective programmes such as STH and CSF markedly improved the cost-effectiveness of the intervention. This is especially important in low resource countries where control of zoonotic neglected tropical diseases could be integrated with the human and animal health sectors to optimize use of the limited resources.

Trial registration

Australia New Zealand Clinical Trials Registry (ANZCTR) ACTRN12614001067662.

Clinical manifestations of dengue in relation to dengue serotype and genotype in Malaysia: A retrospective observational study

18 September 2018 - 9:00pm

by Jeyanthi Suppiah, Siew-Mooi Ching, Syafinaz Amin-Nordin, Lailatul-Akmar Mat-Nor, Naematul-Ain Ahmad-Najimudin, Gary Kim-Kuan Low, Manisya-Zauri Abdul-Wahid, Ravindran Thayan, Hui-Yee Chee

Background

Malaysia experienced an unprecedented dengue outbreak from the year 2014 to 2016 that resulted in an enormous increase in the number of cases and mortality as compared to previous years. The causes that attribute to a dengue outbreak can be multifactorial. Viral factors, such as dengue serotype and genotype, are the components of interest in this study. Although only a small number of studies investigated the association between the serotype of dengue virus and clinical manifestations, none of these studies included analyses on dengue genotypes. The present study aims to investigate dengue serotype and genotype-specific clinical characteristics among dengue fever and severe dengue cases from two Malaysian tertiary hospitals between 2014 and mid-2017.

Methodology and principal findings

A total of 120 retrospective dengue serum specimens were subjected to serotyping and genotyping by Taqman Real-Time RT-PCR, sequencing and phylogenetic analysis. Subsequently, the dengue serotype and genotype data were statistically analyzed for 101 of 120 corresponding patients’ clinical manifestations to generate a descriptive relation between the genetic components and clinical outcomes of dengue infected patients. During the study period, predominant dengue serotype and genotype were found to be DENV 1 genotype I. Additionally, non-severe clinical manifestations were commonly observed in patients infected with DENV 1 and DENV 3. Meanwhile, patients with DENV 2 infection showed significant warning signs and developed severe dengue (p = 0.007). Cases infected with DENV 2 were also commonly presented with persistent vomiting (p = 0.010), epigastric pain (p = 0.018), plasma leakage (p = 0.004) and shock (p = 0.038). Moreover, myalgia and arthralgia were highly prevalent among DENV 3 infection (p = 0.015; p = 0.014). The comparison of genotype-specific clinical manifestations showed that DENV 2 Cosmopolitan was significantly common among severe dengue patients. An association was also found between genotype I of DENV 3 and myalgia. In a similar vein, genotype III of DENV 3 was significantly common among patients with arthralgia.

Conclusion

The current data contended that different dengue serotype and genotype had caused distinct clinical characteristics in infected patients.

Outbreak of human brucellosis in Southern Brazil and historical review of data from 2009 to 2018

18 September 2018 - 9:00pm

by Tamilly Silva Lemos, Juliana Clelia Cequinel, Tania Portela Costa, Amanda Boni Navarro, Andressa Sprada, Flávia Kazumi Shibata, Regina Gondolfo, Felipe Francisco Tuon

Background

Human brucellosis (HB) is a bacterial zoonosis that is more frequent in low income and middle-income countries; it is sometimes associated with outbreaks. The aim of this study was to describe the largest outbreak of HB in Brazil.

Methods

A retrospective cohort study of patients suspected of having contracted HB in the state of Paraná, Southern Brazil from January 2009 to January 2017. Following an outbreak of 51 cases of HB in a slaughterhouse at Paiçandu in 2014, HB was defined as an obligatory reportable disease in the State. Diagnostic tests for HB included serum agglutination, ELISA (IgG or IgM) and polymerase chain reaction (PCR). Clinical, laboratorial and epidemiological data were analyzed. A P value of 0.05 was considered statistically significant.

Results

Out of a total of 3,941 patients, 754 presented with a positive test result for HB. After 2014, there was a significant increase in the number of cases, exceeding 100 cases per trimester. In the beginning of 2015, the workgroup of HB started several actions for prevention and treatment, and the number of cases progressively diminished to fewer than 20 cases per trimester. Of 191 reported cases, an occupational risk was found in 84.7%; most cases occurred in farmers (60.0%), veterinarians (17.6%) and slaughterhouse workers (14.7%). Manipulation of animals and unpasteurized milk consumption were associated with positive Brucella IgM ELISA with an odds ratio (OR) of 1.42 (1.09–1.84) and 1.48 (1.01–2.15), respectively.

Conclusions

HB outbreaks can occur in low to middle-income countries and are associated with slaughterhouse work, handling of unpasteurized milk and animal manipulation. Intensive programs for control of HB are important to reduce the number of cases.

Impact of repeated annual community directed treatment with ivermectin on loiasis parasitological indicators in Cameroon: Implications for onchocerciasis and lymphatic filariasis elimination in areas co-endemic with <i>Loa loa</i> in Africa

18 September 2018 - 9:00pm

by Samuel Wanji, Winston Patrick Chounna Ndongmo, Fanny Fri Fombad, Jonas Arnaud Kengne-Ouafo, Abdel Jelil Njouendou, Yolande Flore Longang Tchounkeu, Benjamin Koudou, Moses Bockarie, Grace Fobi, Jean Baptiste Roungou, Peter A. Enyong

Background

Loiasis is a filarial infection endemic in the rainforest zone of west and central Africa particularly in Cameroon, Gabon, Republic of Congo, and Democratic Republic of the Congo. Repeated treatments with ivermectin have been delivered using the annual community directed treatment with ivermectin (CDTI) approach for several years to control onchocerciasis in some Loa loa-Onchocerca volvulus co-endemic areas. The impact of CDTI on loiasis parasitological indicators is not known. We, therefore, designed this cross sectional study to explore the effects of several rounds of CDTI on parasitological indicators of loiasis.

Methodology/Principal findings

The study was conducted in the East, Northwest and Southwest 2 CDTI projects of Cameroon. Individuals who consented to participate were interviewed for ivermectin treatment history and enrolled for parasitological screening using thick smears. Ivermectin treatment history was correlated with loiasis prevalence/intensity. A total of 3,684 individuals were recruited from 36 communities of the 3 CDTI projects and 900 individuals from 9 villages in a non-CDTI district. In the East, loiasis prevalence was 29.3% (range = 24.2%–34.6%) in the non-CDTI district but 16.0% (3.3%–26.6%) in the CDTI district with 10 ivermectin rounds (there were no baseline data for the latter). In the Northwest and Southwest 2 districts, reductions from 30.5% to 17.9% (after 9 ivermectin rounds) but from 8.1% to 7.8% (not significantly different after 14 rounds) were registered post CDTI, respectively. Similar trends in infection intensity were observed in all sites. There was a negative relationship between adherence to ivermectin treatment and prevalence/intensity of infection in all sites. None of the children (aged 10–14 years) examined in the East CDTI project harboured high (8,000–30,000 mf/ml) or very high (>30,000 mf/ml) microfilarial loads. Individuals who had taken >5 ivermectin treatments were 2.1 times more likely to present with no microfilaraemia than those with less treatments.

Conclusion

In areas where onchocerciasis and loiasis are co-endemic, CDTI reduces the number of, and microfilaraemia in L. loa-infected individuals, and this, in turn, will help to prevent non-neurological and neurological complications post-ivermectin treatment among CDTI adherents.

A Delphi consultation to assess indicators of readiness to provide quality health facility-based Lymphoedema management services

18 September 2018 - 9:00pm

by Victoria L. Walsh, LeAnne M. Fox, Molly Brady, Jonathan King, Caitlin M. Worrell

Background

The World Health Organization (WHO) in collaboration with partners is developing a toolkit of resources to guide lymphatic filariasis (LF) morbidity management and disability prevention (MMDP) implementation and evaluation. Direct health facility inspection is the preferred method for documenting the readiness of a country programme to provide quality lymphoedema management services, one of the three MMDP criteria used to demonstrate the elimination of LF as a public health problem.

Methodology/Principal findings

As component of tool development, a Delphi consultation was implemented to gain consensus on six proposed domains and fourteen proposed tracer indicators to measure national programme readiness to provide quality health facility-based lymphoedema management services. A seven-point Likert-type scale was used to rank the importance of proposed domains and tracer indicators. Consensus for inclusion of the indicator was defined a priori as 70% or more of respondents ranking the proposed indicator in the top three tiers (5–7). Purposive sampling was used to select 43 representative experts including country representatives, programme implementers, and technical experts. A 55.8% response rate (n = 24) was achieved for the survey. Analysis of the responses demonstrated that consensus for inclusion had been reached for all proposed domains including trained staff (mean = 6.9, standard deviation (SD) = 0.34), case management and education materials (mean = 6.1, SD = 0.65), water infrastructure (mean = 6.3, SD = 0.81), medications and commodities (mean = 6.3, SD = 0.69), patient tracking system (mean = 6.3, SD = 0.85), and staff knowledge (mean = 6.5, SD = 0.66).

Significance

The Delphi consultation provided an efficient and structured method for gaining consensus among lymphatic filariasis experts around key lymphoedema management quality indicators. The results from this analysis were used to refine the indicators included within the direct inspection protocol tool to ensure its ability to assess health facility readiness to provide quality lymphoedema management services.

Estimating the efficacy of community-wide use of systemic insecticides in dogs to control zoonotic visceral leishmaniasis: A modelling study in a Brazilian scenario

17 September 2018 - 9:00pm

by Sonia A. Gomez, Lloyd A. C. Chapman, Erin Dilger, Orin Courtenay, Albert Picado

Systemic insecticides in dogs have been suggested as a public health intervention to prevent human cases of Zoonotic Visceral Leishmaniasis (ZVL). But, currently there are no systemic insecticides for dogs registered against zoo-anthropophilic pool blood feeding phlebotomine flies. We predict the impact of community-wide use of systemic insecticide in dog populations as a public health measure to control transmission of Leishmania infantum to humans using a mathematical model. We developed a Susceptible-Exposed-Infected (SEI) compartmental model to describe L. infantum transmission dynamics in dogs, with a vectorial capacity term to represent transmission between L. infantum-hosting dogs via phlebotomine flies. For Infected (I) dogs two levels of infectiousness were modelled, high infectiousness and low infectiousness. Human incidence was estimated through its relationship to infection in the dog population. We evaluated outcomes from a wide range of scenarios comprising different combinations of initial insecticide efficacy, duration of insecticide efficacy over time, and proportion of the dog population treated (60%, 70% & 80%). The same reduction in human infection incidence can be achieved via different combinations of insecticide efficacy, duration and dog coverage. For example, a systemic insecticide with an initial efficacy of 80% and 6 months above 65% efficacy would require treating at least 70% of the dogs to reduce the human infection incidence by 50%. Sensitivity analysis showed that the model outcome was most sensitive to baseline values of phlebotomine fly daily survival rate and insecticide coverage. Community-wide use of systemic insecticides applied to the “L. infantum canine reservoir” can significantly reduce human incidence of L. infantum infection. The results of this mathematical model can help defining the insecticide target product profile and how the insecticide should be applied to maximise effectiveness.

Phospho-proteomic analysis of primary human colon epithelial cells during the early <i>Trypanosoma cruzi</i> infection phase

17 September 2018 - 9:00pm

by Shankar Suman, Girish Rachakonda, Sammed N. Mandape, Shruti S. Sakhare, Fernando Villalta, Siddharth Pratap, Maria F. Lima, Pius N. Nde

The protozoan parasite Trypanosoma cruzi, the causative agent of Chagas disease, causes severe morbidity and mortality in afflicted individuals. About 30% of T. cruzi-infected individuals present with cardiac, gastrointestinal tract, and/or neurological disorders. Megacolon, one of the major pathologies of Chagas disease, is accompanied by gastrointestinal motility disorders. The molecular mechanism of T. cruzi-mediated megacolon in Chagas disease is currently unknown. To decipher the molecular mechanism of T. cruzi-induced alteration in the colon during the early infection phase, we exposed primary human colonic epithelial cells (HCoEpiC) to invasive T. cruzi trypomastigotes at multiple time points to determine changes in the phosphoprotein networks in the cells following infection using proteome profiler Human phospho-kinase arrays. We found significant changes in the phosphorylation pattern that can mediate cellular deregulations in colonic epithelial cells after infection. We detected a significant increase in the levels of phosphorylated heat shock protein (p-HSP) 27 and transcription factors that regulate various cellular functions, including c-Jun and CREB. Our study confirmed significant upregulation of phospho (p-) Akt S473, p-JNK, which may directly or indirectly modulate CREB and c-Jun phosphorylation, respectively. We also observed increased levels of phosphorylated CREB and c-Jun in the nucleus. Furthermore, we found that p-c-Jun and p-CREB co-localized in the nucleus at 180 minutes post infection, with a maximum Pearson correlation coefficient of 0.76±0.02. Increased p-c-Jun and p-CREB have been linked to inflammatory and profibrotic responses. T. cruzi infection of HCoEpiC induces an increased expression of thrombospondin-1 (TSP-1), which is fibrogenic at elevated levels. We also found that T. cruzi infection modulates the expression of NF-kB and JAK2-STAT1 signaling molecules which can increase pro-inflammatory flux. Bioinformatics analysis of the phosphoprotein networks derived using the phospho-protein data serves as a blueprint for T. cruzi-mediated cellular transformation of primary human colonic cells during the early phase of T. cruzi infection.

Corneal complications following Post Kala-azar Dermal Leishmaniasis treatment

17 September 2018 - 9:00pm

by Shomik Maruf, Proggananda Nath, Muhammad Rafiqul Islam, Fatima Aktar, Azim Anuwarul, Dinesh Mondal, Ariful Basher

Post Kala-azar Dermal Leishmaniasis (PKDL) is a sequel of Visceral Leishmaniasis (VL). The patients act as a reservoir for the causative parasite (i.e. Leishmania donovani) and thus should be diagnosed and treated with the utmost urgency to prevent the transmission of the disease. In this study, we tried to report the first instances of corneal complications supposedly associated with Miltefosine (MF), in PKDL patients and the probable pathophysiology of such events. The recently rejuvenated National Kala-azar Elimination Program in Bangladesh has put great emphasis on monitoring all the leishmaniasis patients to investigate possible adverse drug reactions (ADR). A total of 194 patients have received Miltefosine for the treatment of Post Kala-azar Dermal Leishmaniasis. So far five patients were found to have developed unilateral ophthalmic complications during the periods from May 2016 to October 2017, after being treated with MF for PKDL. Unfortunately, one of whom had to go through complete evisceration of the affected eyeball. Despite the fact that MF is the only oral formulation of choice to treat PKDL, occurrences of such unexpected ADRs after MF administration urges the exploration of the pathogenesis of such incidents and determine measures to avert such occurrences from happening in future.

Towards elimination of lymphatic filariasis in southeastern Madagascar: Successes and challenges for interrupting transmission

17 September 2018 - 9:00pm

by Andres Garchitorena, Estelle M. Raza-Fanomezanjanahary, Sedera A. Mioramalala, Cedric Chesnais, Claude A. Ratsimbasoa, Herinirina Ramarosata, Matthew H. Bonds, Holivololona Rabenantoandro

Introduction

A global strategy of mass drug administration (MDA) has greatly reduced the burden of lymphatic filariasis (LF) in endemic countries. In Madagascar, the National Programme to eliminate LF has scaled-up annual MDA of albendazole and diethylcarbamazine across the country in the last decade, but its impact on LF transmission has never been reported. The objective of this study was to evaluate progress towards LF elimination in southeastern Madagascar.

Methods

Three different surveys were carried out in parallel in four health districts of the Vatovavy Fitovinany region in 2016: i) a school-based transmission assessment survey (TAS) in the districts of Manakara Atsimo, Mananjary, and Vohipeno (following a successful pre-TAS in 2013); ii) a district-representative community prevalence survey in Ifanadiana district; and iii) a community prevalence survey in sentinel and spot-check sites of these four districts. LF infection was assessed using the Alere Filariasis Test Strips, which detect circulating filarial antigens (CFA) of adult worms. A brief knowledge, attitudes and practices questionnaire was included in the community surveys.

Principal findings

None of the 1,825 children sampled in the TAS, and only one in 1,306 children from sentinel and spot-check sites, tested positive to CFA. However, CFA prevalence rate in individuals older than 15 years was still high in two of these three districts, at 3.5 and 9.7% in Mananjary and Vohipeno, respectively. Overall CFA prevalence in sentinel and spot-check sites of these three districts was 2.80% (N = 2,707), but only two individuals had detectable levels of microfilaraemia (0.06%). Prevalence rate estimates for Ifanadiana were substantially higher in the district-representative survey (15.8%; N = 545) than in sentinel and spot-check sites (0.8%; N = 618). Only 51.2% of individuals surveyed in these four districts reported taking MDA in the last year, and 42.2% reported knowing about LF.

Conclusions

Although TAS results suggest that MDA can be stopped in three districts of southeastern Madagascar, the adult population still presents high CFA prevalence levels. This discordance raises important questions about the TAS procedures and the interpretation of their results.

PCR-RFLP screening of polymorphisms associated with benzimidazole resistance in <i>Necator americanus</i> and <i>Ascaris lumbricoides</i> from different geographical regions in Brazil

17 September 2018 - 9:00pm

by Luciana Werneck Zuccherato, Luis Fernando Furtado, Celi da Silva Medeiros, Carina da Silva Pinheiro, Élida M. Rabelo

Ascaris lumbricoides and Necator americanus are soil-transmitted parasites with global geographic distribution, and they represent some of the most common and neglected infections in the world. Periodic treatment with mass drug administration (MDA) in endemic areas is the recommended action put forth by the World Health Organization. However, MDA can cause the selection of subpopulations that possess the genetic ability to overcome the mechanism of drug action. In fact, beta-tubulin gene mutations (codons 167, 198 and 200) are correlated with benzimidazole resistance in nematodes of veterinary importance. It is possible that these SNPs also have strong correlation with treatment resistance in the human geohelminths A. lumbricoides, Trichuris trichiura and hookworms. Here, we aimed to investigate the presence of some of these canonical molecular markers associated with parasite resistance to benzimidazole in N. americanus and A. lumbricoides collected from six Brazilian states. Nested-PCR and PCR-RFLP were used to detect mutations at codons 167 and 198 in 601 individual eggs of A. lumbricoides collected from 62 human stool samples; however, no mutations were found. Codons 198 and 200 were tested in 552 N. americanus eggs collected from 48 patients using the same methodology, which presented a relative frequency of 1.4% and 1.1%, respectively. The presence of these SNPs in N. americanus eggs is an important finding, indicating that with high benzimidazole drug pressure there is potential for benzimidazole resistance to be selected in this hookworm. However, at these low frequencies it does not indicate that there is at present any benzimidazole resistance problem. This is the first systematic study performed in South America, and the study yielded a landscape of the genetic variants in the beta-tubulin gene and anthelmintic resistance to soil-transmitted parasites detected by a simple, rapid and affordable genotyping assay of individual eggs.

The association of rainfall and Buruli ulcer in southeastern Australia

17 September 2018 - 9:00pm

by Arvind Yerramilli, Ee Laine Tay, Andrew J. Stewardson, Janet Fyfe, Daniel P. O’Brien, Paul D. R. Johnson

Background

Buruli ulcer has been increasing in incidence in southeastern Australia with unclear transmission mechanisms. We aimed to investigate the link between rainfall and case numbers in two endemic areas of the state of Victoria; the Bellarine and Mornington Peninsulas.

Methodology

We created yearly and monthly graphs comparing rainfall with local Buruli ulcer incidence for the period 2004–2016 by endemic region and then considered a range of time lag intervals of 0–24 months to investigate patterns of correlation.

Conclusions

Optimal positive correlation for the Bellarine Peninsula occurred with a 12-month prior rainfall lag, however, no significant correlation was observed on the Mornington Peninsula for any time lag. These results provide an update in evidence to further explore transmission mechanisms which may differ between these geographically proximate endemic regions.

Rural youths' understanding of gene x environmental contributors to heritable health conditions: The case of podoconiosis in Ethiopia

13 September 2018 - 9:00pm

by Kibur Engdawork, Colleen M. McBride, Desta Ayode, Caitlin G. Allen, Gail Davey, Getnet Tadele

Objectives

Assess the feasibility of engaging youth to disseminate accurate information about gene by environmental (GxE) influences on podoconiosis, a neglected tropical lymphedema endemic in southern Ethiopia.

Methods

A cross sectional survey was conducted with 377 youth randomly selected from 2 districts of Southern Ethiopia. Measures included GxE knowledge (4 true/false statements), preventive action knowledge (endorse wearing shoes and foot hygiene), causal misconceptions (11 items related to contagion) and confidence to explain GxE (9 disagree/agree statements).

Results

Over half (59%) accurately endorsed joint contributions of gene and environment to podoconiosis and preventive mechanisms (e.g., wearing protective shoes and keeping foot hygiene). Multivariable logistic regression showed that youth with accurate understanding about GxE contributors reported having: some education, friends or kin who were affected by the condition, and prior interactions with health extension workers. Surprisingly, higher accurate GxE knowledge was positively associated with endorsing contagion as a causal factor. Accuracy of GxE and preventive action knowledge were positively associated with youth’s confidence to explain podoconiosis-related information.

Conclusions

Youth have the potential to be competent disseminators of GxE information about podoconiosis. Interventions to foster confidence among youth in social or kin relationships with affected individuals may be most promising. Efforts to challenge youth’s co-existing inaccurate beliefs about contagion could strengthen the link of GxE explanations to preventive actions.

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