Occurrence Of Human Cases Research Articles

Population dynamics of plague vector fleas in an endemic focus: implications for plague surveillance.

Plague is a zoonotic vector-borne disease caused by the bacterium Yersinia pestis. In Madagascar, it persists in identified foci, where it is a threat to public health generally from September to April. A more complete understanding of how the disease persists could guide control strategies. Fleas are the main vector for transmission between small mammal hosts and humans, and fleas likely play a role in the maintenance of plague. This study characterized the dynamics of flea populations in plague foci alongside the occurrence of human cases. From 2018 to 2020, small mammals were trapped at sites in the central Highlands of Madagascar. A total of 2,762 small mammals were captured and 5,295 fleas were collected. The analysis examines 2 plague vector species in Madagascar (Synopsyllus fonquerniei and Xenopsylla cheopis). Generalized linear models were used to relate flea abundance to abiotic factors, with adjustments for trap location and flea species. We observed significant effects of abiotic factors on the abundance, intensity, and infestation rate by the outdoor-associated flea species, S. fonquerniei, but weak seasonality for the indoor-associated flea species, X. cheopis. A difference in the timing of peak abundance was observed between the 2 flea species during and outside the plague season. While the present study did not identify a clear link between flea population dynamics and plague maintenance, as only one collected X. cheopis was infected, the results presented herein can be used by local health authorities to improve monitoring and control strategies of plague vector fleas in Madagascar.

Surveillance of Human Cases of Salmonellosis, Campylobacteriosis, Listeriosis, and Hepatitis A in Campania (Southern Italy): Seven-Year Monitoring (2013–2019)

Foodborne infections cause illness and death every year worldwide. The aim of this study was to describe trends in 2013-2019 in the occurrence of human cases of salmonellosis, campylobacteriosis, listeriosis, and hepatitis A in the Campania region. Human case data were provided by the National Surveillance System of disease and were grouped by year, province, age group, and sex. Moreover, the number of people hospitalized was recorded. In the Campania region, the total number of confirmed human cases for the diseases investigated was 1924, with Hepatitis A and the Salmonellosis as the first most reported (1009 and 825 cases, respectively). The incidence rates of gastroenteritis under study were lower than those in Italy and European Union in the same period, with the exception of Hepatitis A whose incidence was higher than that recorded in Italy. Data on hospitalizations pointed out the onset of severe forms of infection also for listeriosis and campylobacteriosis, whose incidence was very low (27 and 63 cases, respectively). Unfortunately, no information on the foods implicated is available. Although probably underestimated, gastroenteritis due to foodborne agents still represents a burden in Campania, and continuous monitoring and implementation of the currently available regional surveillance system is required.

Interaction of Haemagogus leucocelaenus (Diptera: Culicidae) and Other Mosquito Vectors in a Forested Area, Rio de Janeiro, Brazil.

The yellow fever (YF) virus has been detected throughout Brazil, with the occurrence of human cases, cyclic epizootics, and its isolation from Haemagogus janthinomys and Hg. leucocelaenus. We assessed the seasonal occurrence, egg abundancy, and oviposition interaction of mosquito vector species captured at a Private Natural Heritage Reserve in the Atlantic Forest biome. A total of 2943 eggs and 1538 mosquito larvae were collected from which 1231 belonged to entomologically important species. Ovitraps were used to collect immature mosquitoes from September 2019 to January 2021. The Mann–Whitney test was used to assess the differences in the abundance of eggs between rainy and dry seasons. Kruskal–Wallis and Dunn’s post hoc tests were used to evaluate the significance of the differences in the number of individuals from vector species. The highest percentage of mosquito vector eggs were collected during the rainy season, from December to February. Most eggs recovered from ovitraps belonged to the species Hg. leucocelaenus, representing 85% of all mosquito eggs identified. The other species had lower abundances and percentages: Aedes terrens (7%), Haemagogus janthinomys (5%) and Aedes albopictus (3%). The species that shared breeding sites with a higher frequency were Hg. leucocelaenus and Hg. janthinomys, with a statistically positive correlation (ρ = 0.74). This finding suggests that maybe the presence of Hg. leucocelaenus eggs acted as an attractant for Hg. janthinomys or vice versa. An understanding of mosquito oviposition behavior is necessary for the development of surveillance and control approaches directed against specific pathogen vectors of medical and veterinary importance.

Sero-positivity of Japanese Encephalitis Virus in Equine Population of India Using IgG ELISA: Unraveling the Need for Vaccination

Japanese encephalitis (JE) is a mosquito borne flaviviral zoonoses, causing fatal disease in equines and humans. JE is endemic in most of the states of India with occurrence of human cases every year. The horses are not vaccinated against JE in India and thus they are at more risk of acquiring the disease. Due to nonavailability of indigenously developed ELISA and high cost of imported kits, regular sero-surveillance is not being carried out to assess the true picture of JE virus in equine population of India. Therefore, a recombinant NS1 protein based indirect IgG ELISA was developed with the objective to assess the sero-positivity of JE virus in equine population of India. The diagnostic sensitivity and specificity of developed ELISA was 84.73% and 86.70%, respectively. The validation studies revealed good reproducibility of ELISA with kappa value ranging from 0.75 to 1 between the results of different laboratories. A total of 2,069 horse serum samples were screened using the developed ELISA and 401 samples were positive for IgG against JEV with an overall sero-positivity of 19.38% in equine population of India. A sero-positivity of 25.90% and 12.22% was recorded in Himachal Pradesh and Jammu-Kashmir, both hill states of North zone of India for the first time, revealing the spread of virus to the nonendemic parts of the country. The high sero-positivity of JE virus recorded in equine population warrants the need for initiation of vaccination of horses in India to prevent the morbidity and mortality.

Application of Relational Bayesian Networks to Vector Control in New York City

We propose a novel way of rapidly formulating hypotheses describing the efficacy of West Nile virus (WNV) control campaigns using relational Bayesian Networks (RBN). RBN takes advantage of both quantitative information and expert opinion. We used multiyear, geo-referenced, and temporal data about dead birds, mosquitoes and humans, to infer probable relationships using proprietary software (CleverSet® Modeler) and discover the RBN that best fit the data for our initial models. Additional expert knowledge was later utilized for augmenting subsequent models. The final RBM was created after relating all the variables of interest that correlate to the occurrence of human cases, positive birds, and positive mosquitoes. The findings of this research suggest that WNV positive birds are valuable indicators of WNV activity. The most probable core organisms are bird-feeding Culex and ground-dwelling birds. WNV preventive measures such as public education, source reduction, and larviciding may be supplemented by adult mosquito control by ground spraying. To effectively interrupt the chain of transmission, careful effort must be devoted to ensuring that fewer mosquitoes remain the day after spray.

Multi‐country outbreak of multiple Salmonella enterica serotypes linked to imported sesame‐based products

Since January 2019, 121 cases of Salmonella enterica infections with six different serotypes linked to sesame-based products have been reported in five EU/EEA countries. The serotypes are S. Amsterdam, S. Havana, S. Kintambo, S. Mbandaka, S. Orion, and S. Senftenberg. Case interviews in four countries revealed consumption of sesame-based products (halva or tahini) prior to illness. Almost half of the cases are in children ≤10 years, who also represent over half of hospitalised cases. No deaths have been reported. Since November 2019, 14 batches of sesame-based products originating from Syria, tested positive for one or multiple Salmonella outbreak strains (twelve from Brand A, two from Brand C). Based on available epidemiological, microbiological, and traceability information, the probable vehicles of infection are sesame-based products imported from Syria, at least in countries involved in the traceability of the positive batches. These products are sealed and ready to be consumed, suggesting that the contamination occurred before the products reached the European Union/European Economic Area (EU/EEA) market. The intermittent occurrence of human cases and the identification of positive food samples since 2019 indicate the availability of the contaminated sesame-based products on the EU/EEA market for over two years. This has posed a risk for human infections and severe clinical illness with several Salmonella serotypes, particularly among children. Control measures implemented since August 2020 on the involved batches of sesame-based products have not prevented the occurrence of human cases to date. Moreover, the concerned products have a long shelf life and might still be stored in people’s homes. Considering the limited information on product manufacturing and distribution, there remains a risk for new Salmonella infections in the EU/EEA linked to imported sesame-based products from Syria.

917Stakeholder analysis to develop a national outbreak response plan for Q fever in Australia

917Stakeholder analysis to develop a national outbreak response plan for Q fever in Australia

Serological study of American Tegumentary Leishmaniasis in working horses and contact dogs in the city of Bandeirantes, Parana

The American Tegumentary Leishmaniasis (ATL) occurs in several parts of the world, in Brazil and also in the State of Parana, it is a disease of great importance in public health, since it affects animals and humans, with a zoonotic character. Leishmaniasis is found in two forms, tegumentary and visceral, and has sandflies as vectors and wild animals and domestic dogs as reservoirs. ATL is considered an endemic disease in the city of Bandeirantes, with human cases occurring in several urban and rural locations, mainly in areas close to forest remnants, peri-urban and peripheral areas, where vulnerable populations live in general, and with precarious basic sanitation conditions. In these regions also live the participants of the wagon driver project, who own several working horses. The project provides guidance on management, good practices, disease prevention, and animal welfare. Since the role of horses as reservoirs and in the chain of transmission of ATL is not well known, the aim of this study was to carry out a serological study of ATL in horses and in the contact dogs of the participants of the " wagon driver" project, at UENP-CLM, to evaluate seropositivity in these species. Blood samples were collected from 20 horses and 12 contact dogs. A serological study, using the ELISAi test for ATL diagnosis, was carried out on the horses and dogs in relation to this study population, to assess seropositivity. In the serological survey, eight horses out of 20 animals (40%) and four dogs out of 12 animals (33.33%) were seropositive, a result considered significant, indicating the presence of the disease and the risk of transmission where they live. The occurrence of human cases and the presence of ATL vectors have already been identified in several locations in the city. Due to the lack of knowledge about the disease and the difficulty in controlling the vectors, health education is necessary in order to provide the population with orientation on how to prevent the disease, as well as entomological surveillance and new serological studies in areas at risk for ATL transmission. The results indicate that there may be importance in the role of horses as reservoirs and in the transmission of Tegumentary Leishmaniasis, which still needs to be clarified.

Evolution of Rabies in South America and Inter-Species Dynamics (2009-2018).

Rabies is listed as one of the World Health Organisation’s (WHO) Neglected Tropical Diseases Worldwide, with a significant impact in South America. This paper explores the dynamics of rabies cases in humans, pets (dogs and cats), livestock and wildlife (bats in particular) in South America during the period 2009–2018. The data used in this study were derived from the two main databases for rabies in South America: the OIE-WAHIS from the World Organisation for Animal Health (OIE) and PANAFTOSA’s Regional Information System for the Epidemiological Surveillance of Rabies (SIRVERA). Being a neglected disease with possible underreporting in some areas, the reported rabies cases may not always represent the real disease burden. The analysis focuses on the evolution of the number of cases in time and their spatial distribution, as well as on the main source of infections in humans, determined by laboratory assays of the antigenic variant or through epidemiological investigations. Additionally, Generalised Linear Mixed Models (GLMM) were used to evaluate the risk factors associated with the occurrence of human cases. Our results show that the highest impact of the disease in terms of number of cases was reported on livestock, while the overall number of cases (in animals and humans) progressively decreased along the study period. The spatial distribution of rabies in livestock showed two main clusters in the north-western (mainly Colombia) and in the south-eastern part of the affected area (Brazil), and a third smaller cluster in Peru. A cluster in dogs was observed in Bolivia. Out of the 192 human cases reported during the study period, 70% of them were transmitted by bats. The number of human cases reported during the study period were significantly associated with the number of rabies cases reported in livestock, pets and wildlife. Despite the overall decreasing case report rate, the disease still represents a major animal and public health concern in South America, and new strategies for compiling systematic information, networking and education are needed, as well as the education and training of veterinary staff.

Mayaro virus detection in patients from rural and urban areas in Trinidad and Tobago during the Chikungunya and Zika virus outbreaks

ABSTRACT Mayaro virus, which can often go undetected due to its clinical manifestations and intimate alignment with dengue and chikungunya viruses, is one of the most neglected arboviruses. The virus has been found in several outbreaks, where a moderate-to-severe and potentially incapacitating joint disease has been observed. MAYV usually circulates in a sylvan cycle of forest mosquitoes and vertebrates, causing sporadic sylvatic infections to humans, and some outbreaks in sub-urban areas. This study focuses on the demonstration of the possible co-circulation of Mayaro virus with chikungunya virus and Zika virus during the outbreaks that occurred in Trinidad and Tobago in 2014 and 2016, respectively. Acute samples from patients who previously tested negative for chikungunya, dengue, and Zika, and specifically exhibiting joint pain were selected and investigated for the presence of Mayaro virus genome using real-time RT-PCR techniques. Nine persons were shown to be positive for Mayaro virus during the chikungunya outbreak of 2014, while no one during the Zika outbreak in 2016. Five results correspond to persons living in highly urbanized areas across Trinidad. These findings provide evidence that multiple arboviral circulations are possible and could easily go undetected especially during outbreak situations. Our study is the first to demonstrate the possible co-circulation of Mayaro and chikungunya viruses and the occurrence of human cases for both diseases during an outbreak in the Caribbean. A possible change in the pattern of distribution of human cases to more urbanized areas is also discussed.

Spatial association between sporotrichosis in cats and in human during a Brazilian epidemics

Sporotrichosis is a subcutaneous granulomatous disease caused by the fungus Sporothrix spp. In Brazil, S. brasiliensis is reported in regions of outbreaks and epidemics in the zoonotic form of the disease where cats play an important role in the transmission of the disease to humans. Therefore, it is important to assess how the presence of infected cats impacts the risk for sporotrichosis in humans. The objective of this study was to analyze the spatial association of sporotrichosis in cats and in humans from Belo Horizonte, a Brazilian city where an epidemics of sporotrichosis occurs since the first human case register in 2015, through an inhomogeneous Poisson process model. Feline and human cases of sporotrichosis recorded between January 2016 and June 2019 were georeferenced by address and spatial point patterns were generated. Feline case intensity and human demographic density were calculated using a kernel smoothed estimate. The distance to the nearest feline case was also compute. Model parameters were estimated by Maximum Likelihood Estimate. The model validation was performed by the evaluation of partial residual, leverage and influence measure. There were 343 cases of cats and 135 human cases of sporotrichosis. The average incidence of human sporotrichosis in the period was 1.343 per 100 thousand inhabitants, which is relatively low in relation to the population, but higher than that observed in other regions in zoonotic outbreak of the disease. The southern region of the municipality has a higher intensity of feline cases. According to the fitted model, the risk for human sporotrichosis is greater when at distances very close to a feline case, with a virtually stable effect for distances greater than 1 km. Regarding the intensity of feline cases there is a gradual increase in risk as the intensity of cases increases. From the leverage analysis it was observed that the model was particularly sensitive to the occurrence of human cases in the south and east regions, places with extreme values ​​of covariates. Poisson point process model seems to be a reasonable approach in spatial epidemiology when multiple sources of infection are involved, and there is a low incidence of the disease as long as it is reasonable to assume independence between cases. Interventions for disease prevention and control in humans are suggested to encompass disease control in cats and the search for feline cases, focused on diagnosis and control, close to reported human cases.

Identifying the environmental drivers of Campylobacter infection risk in southern Ontario, Canada using a One Health approachs.

Campylobacter bacteria infect both humans and animals. Sources of human exposure include contaminated food and water, contact with animals and/or their faeces, and contact with infected individuals. The objectives of this study were to: (a) identify environmental conditions associated with the occurrence of Campylobacter in humans in four regions of Ontario, and (b) identify pooled measures of effect across all four regions and potential sources of heterogeneity. To address objective 1, human Campylobacter cases from four health regions of Ontario, Canada were analysed using negative binomial regression and case cross-over analysis to identify relationships between environmental factors (temperature, precipitation and hydrology of the local watershed) and the risk of human infection. To address objective 2, meta-analytic models were used to explore pooled measures of effect and when appropriate, meta-regression models were used to explore potential sources of heterogeneity. Human incidence exhibited strong seasonality with cases peaking in the late spring and summer. There was a decreasing yearly effect in three of the four health regions. A significant pooled effect was found for mean temperature after a 1-week lag (OR=1.03, 95% CI 1.02, 1.04). No significant pooled effects were found for precipitation or water flow. However, increased precipitation was associated with lower odds of campylobacteriosis in Wellington and York regions at 2- and 3-week lags, respectively, from the case cross-over analysis. These results demonstrate that a climatic factor (specifically, mean temperature in the week prior) was associated with human case occurrence after a biologically plausible time period, but hydrologic factors are not.

Can local risk of West Nile virus infection be predicted from previous cases? A descriptive study in Quebec, 2011-2016.

This study aimed at (1) describing the local risk of West Nile virus (WNV) infection in humans based on previous case reports and (2) investigating the spatial clustering of cases in the five most affected administrative regions of Quebec, Canada, for the 2011-2016 period. Human WNV cases declared to the Ministry of Health and Social Services of Quebec(Ministère de la santé et des services sociaux, MSSS) were retrieved. Incidence risk by age and sex was calculated for the study period. The yearly and monthly occurrence of cases in geographical units (GUs) was described and the probability of observing cases in a GU with cases reported in the previous year or month was assessed. Moran's I was used to assess global clustering across the study area. Spatial clusters were identified by the Kulldorff scan statistic. A total of 261 WNV cases were declared to the MSSS between 2011 and 2016 in the study area. Overall, a low percentage of GU with cases reported had additional cases reported over the next month or year. Global spatial clustering was weak but statistically significant (p < 0.05) for 2012 and 2015. For these two years, spatial clusters of high-risk GUs were identified. Results underline the challenge of predicting the distribution of WNV incidence risk in Quebec based on previous occurrence of human cases. Ongoing research with high spatial resolution entomological data is still necessary to understand the spatial distribution of risk at a local scale.

Implementation of the One Health approach to fight arbovirus infections in the Mediterranean and Black Sea Region: Assessing integrated surveillance in Serbia, Tunisia and Georgia.

BackgroundIn the Mediterranean and Black Sea Region, arbovirus infections are emerging infectious diseases. Their surveillance can benefit from one health inter‐sectoral collaboration; however, no standardized methodology exists to study One Health surveillance.MethodsWe designed a situation analysis study to document how integration of laboratory/clinical human, animal and entomological surveillance of arboviruses was being implemented in the Region. We applied a framework designed to assess three levels of integration: policy/institutional, data collection/data analysis and dissemination. We tested the use of Business Process Modelling Notation (BPMN) to graphically present evidence of inter‐sectoral integration.ResultsSerbia, Tunisia and Georgia participated in the study. West Nile Virus surveillance was analysed in Serbia and Tunisia, Crimea‐Congo Haemorrhagic Fever surveillance in Georgia. Our framework enabled a standardized analysis of One Health surveillance integration, and BPMN was easily understandable and conducive to detailed discussions among different actors/institutions. In all countries, we observed integration across sectors and levels except in data collection and data analysis. Data collection was interoperable only in Georgia without integrated analysis. In all countries, surveillance was mainly oriented towards outbreak response, triggered by an index human case.DiscussionThe three surveillance systems we observed prove that integrated surveillance can be operationalized with a diverse spectrum of options. However, in all countries, the integrated use of data for early warning and inter‐sectoral priority setting is pioneeristic. We also noted that early warning before human case occurrence is recurrently not operationally prioritized.

An autochthonous case of visceral canine leishmaniasis in Barra do Piraí-RJ

Visceral Leishmaniasis, a disease caused by the protozoan Leishmania chagasi, is a re-emergent anthropozoonosis, considered a major public health problem. In the urban area, the dog (Canis familiaris) is the main source of infection and canine enzootia has preceded the occurrence of human cases, in which infection in dogs has been more prevalent than in humans. In this context, the present study reports the occurrence of an autochthonous case of Visceral Canine Leishmaniasis in Barra do Pirai, RJ. After verification of a clinic compatible with canine visceral leishmaniasis, several diagnostic exams were performed, such as cytological examination of the ear tip and lymph node puncture, rapid immunochromatographic test DPP® (Dual Path Platform), ELISA, RIFI and culture of material obtained from of skin biopsy, lymph node and bone marrow puncture. With the clinical, serological and parasitological confirmation of Leishmania spp. the dog’s owner chose to euthanize this animal and 3 months later, another positive animal residing in the same place. Based on this report, it is necessary to implement the entomological and epidemiological surveillance in the county of Barra do Pirai, in order to detect the presence of the vector and / or canine enzootia prior to the installation of the anthropozoonotic cycle, allowing to adopt actions to control the disease and the occurrence of the disease in humans.

Dispersion of Lutzomyia longipalpis and expansion of visceral leishmaniasis in S\xe3o Paulo State, Brazil: identification of associated factors through survival analysis

BackgroundIn Brazil, visceral leishmaniasis (VL) is a serious public health problem because of its magnitude, geographical expansion and potential harms caused by illnesses, including death. However, VL is largely ignored in discussions of tropical disease priorities. Thus, this study aimed to identify factors associated with the expansion of VL and the dispersion of its vector, Lutzomyia longipalpis, in the municipalities of the State of São Paulo, Brazil.MethodsInformation about the date of vector detection and the confirmation of autochthonous VL occurrence in humans and canines in São Paulo were obtained between 1997 and 2014. Survival curves were calculated by the Kaplan-Meier and the Cox multiple regression models was used.ResultsThe presence of the Marechal Rondon highway showed the highest positive association with vector dispersion and canine and human VL expansion. The monthly maximum and minimum temperature averages recorded in the municipalities during the study period were also positively associated with these events. The presence of transverse highways was positively associated with the presence of the vector; the border with the State of Mato Grosso do Sul, the presence of a prison, microregion headquarters, and the presence of the Tietê River were positively associated with the occurrence of canine cases, while only the presence of prison was positively associated with the occurrence of human cases. The construction of the Bolivia-Brazil gas pipeline was not associated with any events.ConclusionsSurvival analysis enabled the identification of factors associated with vector dispersion and VL expansion, thus the results of this study may be useful to the improvement of VL surveillance and control activities in the State of São Paulo and throughout Brazil.

Assessing the impact of environmental exposures and Cryptosporidium infection in cattle on human incidence of cryptosporidiosis in Southwestern Ontario, Canada.

Cryptosporidium is a waterborne parasite that causes diarrheal disease in humans and in cattle. Risk factors for human illness include contact with surface water such as lakes and rivers, exposure to contaminated municipal drinking water, as well as zoonotic transmission from livestock and agriculture. The objectives of this study are twofold: 1) to describe the temporal distribution of cryptosporidiosis in Southwestern Ontario; and 2) to determine the distribution of human cryptosporidiosis, in relation to exposures such as cryptosporidium positive cattle farms, weather events, and hydrological factors. Seasonal trends in 214 bovine and 87 human cases were assessed using regression models that predicted monthly case counts in relation to observed monthly case counts. A case-crossover approach was used to evaluate acute associations between daily environmental exposures, such as weather, hydrology, the presence of Cryptosporidium positive cattle farms within the region, and the risk of human Cryptosporidium infection. Annual seasonality was found for both human cases and bovine cases with human cases peaking in mid-summer and bovine cases peaking in late winter to early spring. Bovine cases that occurred 21 days prior to human cases were associated with a three-fold increase in the odds of human case occurrence. At both 9 and 14 days prior to human case onset, the odds of a human case increased twofold per 10-degree Celsius increase in air temperature. These results provide a preliminary hypothesis for the zoonotic transmission of cryptosporidiosis from cattle to humans via the environment and suggest that the timing of environmental conditions in relation to case occurrence is biologically plausible.

Taenia solium, Taenia saginata, Taenia asiatica, their hybrids and other helminthic infections occurring in a neglected tropical diseases' highly endemic area in Lao PDR.

Most part of Southeast Asia is considered endemic for human-infecting Taenia tapeworms; Taenia solium, T. saginata, and T. asiatica. However, until now there was no report of the occurrence of human cases of T. asiatica in Lao PDR. This study, conducted in Savannakhet Province, Lao PDR, microscopically examined a total of 470 fecal samples by Kato Katz method and found 86% of people harboring at least one helminth. Hookworms were detected in 56% of the samples besides Opisthorchis like eggs (42%), Trichuris trichiura (27%), Ascaris spp. (14%), and Taenia spp. (4%) eggs. Serology for cysticercosis showed 6.8% positives with results varying from 3% to 14.3% in Ethnic School students and Kalouk Kao village respectively. Species-specific PCR targeting mitochondrial DNA (mtDNA) of 28 tapeworms, recovered from 16 patients, revealed T. solium (n = 2), T. saginata (n = 21), and T. asiatica (n = 5). Two patients were confirmed to be coinfected with T. saginata and T. asiatica, indicating the endemicity of the 3 human Taenia in Lao PDR. However, nucleotide sequencing of a nuclear DNA gene, DNA polymerase delta (pold) revealed that all the tapeworms identified as T. asiatica using mtDNA had T. saginata type allele at pold locus, demonstrating that they are not “pure T. asiatica” but the hybrid descendants between the two species, confirming the wide distribution of hybrids of T. saginata/ T. asiatica in Southeast Asia. The high prevalence of several helminthic NTDs in east Savannakhet area even with conventional control measures indicates the importance to establish wide and multifaceted health programs to sustainably improve the quality of life of the populations living in these communities.

Correlations Between Environmental Factors and Increasing Lyme Disease Incidence in Canada

BackgroundLyme disease (LD) is an emerging infectious disease in Canada due to northward expansion of the geographic range of Ixodes scapularis, the principal tick vector for the LD agent Borrelia burgdorferi, into central and eastern Canada. This study aims to i) summarize the surveillance data for LD cases reported in Canada between 2009 and 2015, ii) identify potential environmental risk factors and iii) develop an acarological risk indicator from passive surveillance for occurrence of human cases.MethodsWe described the distribution, trends, demographic and clinical characteristics of cases of the disease. Logistic regression models were used to identify risk factors for the occurrence of LD: 1) demographic (age and sex), and 2) environmental (type of forest cover, temperature and abundance of ticks). Passive surveillance data were used to develop an acarological indicator of at-risk areas for LD.ResultsThe number of reported LD cases increased more than six-fold overall, from 144 cases in 2009 to 917 cases in 2015, mainly due to locally acquired infections. LD incidence in Nova Scotia has risen sharply since 2013 and was the highest in Canada over the study period. Children below 15 years and adults of the 55–74 age groups reported highest incidence. Significantly more men than women were infected and men had significantly more symptoms of late disseminated LD than women. Variability in clinical manifestations is observed between provinces, years, for children below 15 years and between age groups. The majority of cases were reported between April and November and there was an increase in risk areas. The abundance of Ixodes scapularis ticks collected on humans and deciduous forest cover were significantly associated with the occurrence of LD cases at the municipality scale. Passive surveillance provides a cost-effective alert tool for public health authorities to timely identify risk areas and target vulnerable populations and front-line health professionals by means of awareness campaigns.ConclusionThese findings showed that LD continues to increase in Canada, both over time and geographically, underlining the need to implement better preventive strategies, early disease recognition and treatment and efficient surveillance systems.Disclosures All authors: No reported disclosures.

The Rapid Test Based on Leishmania infantum Chimeric rK28 Protein Improves the Diagnosis of Canine Visceral Leishmaniasis by Reducing the Detection of False-Positive Dogs.

Visceral Leishmaniasis (VL) has spread to many urban centers worldwide. Dogs are considered the main reservoir of VL, because canine cases often precede the occurrence of human cases. Detection and euthanasia of serologically positive dogs is one of the primary VL control measures utilized in some countries, including Brazil. Using accurate diagnostic tests can minimize one undesirable consequence of this measure, culling false-positive dogs, and reduce the maintenance of false-negative dogs in endemic areas. In December 2011, the Brazilian Ministry of Health replaced the ELISA (EIE CVL) screening method and Indirect Immunofluorescence Test (IFI CVL) confirmatory method with a new protocol using the rapid DPP CVL screening test and EIE CVL confirmatory test. A study of diagnostic accuracy of these two protocols was done by comparing their performance using serum samples collected from a random sample of 780 dogs in an endemic area of VL. All samples were evaluated by culture and real time PCR; 766 out of the 780 dogs were tested using the previous protocol (IFI CVL + EIE CVL) and all 780 were tested using the current protocol (DPP CVL + EIE CVL). Performances of both diagnostic protocols were evaluated using a latent class variable as the gold standard. The current protocol had a higher specificity (0.98 vs. 0.95) and PPV (0.83 vs. 0.70) than the previous protocol, although sensitivity of these two protocols was similar (0.73). When tested using sera from asymptomatic animals, the current protocol had a much higher PPV (0.63 vs. 0.40) than the previous protocol (although the sensitivity of either protocol was the same, 0.71). Considering a range of theoretical CVL prevalences, the projected PPVs were higher for the current protocol than for the previous protocol for each theoretical prevalence value. The findings presented herein show that the current protocol performed better than previous protocol primarily by reducing false-positive results.