Zika, dengue and chikungunya population prevalence in Rio de Janeiro city, Brazil, and the importance of seroprevalence studies to estimate the real number of infected individuals.

In the last 40 years, Latin America countries, including Brazil, have suffered from the emergence and reemergence of arboviruses, first Dengue (DENV) and recently Zika (ZIKV) and Chikungunya (CHIKV). All three arboviruses are currently endemic in Brazil and have caused major outbreaks in recent years. Rio de Janeiro city, host of the last Summer Olympic Games and the Football World Cup, has been specially affected by them. A surveillance system based on symptomatic reports is in place in Rio, but the true number of affected individuals is unknown due to the great number of Zika, Dengue and Chikungunya asymptomatic cases. Seroprevalence studies are more suitable to evaluate the real number of cases in a given population. We performed a populational seroprevalence survey in Rio, with recruitment of a sample of volunteers of all ages and gender from July to October 2018, within randomly selected census tracts and household. A total of 2,120 volunteers were interviewed and tested with rapid immunochromatographic test for ZIKV, DENV and CHIKV. Individuals with positive results for IgG and/or IgM from only one virus were classified accordingly, while those with test results positive for both ZIKV and DENV were classified as flaviviruses. We corrected for sample design and non-response in data analysis, and calculated point estimate prevalence and 95% confidence intervals for each virus. Arbovirus prevalence in the Rio's population (n = 6,688,927) was estimated at 48.6% [95% CI 44.8-52.4] (n = 3,254,121) for flaviviruses and at 18.0% [95% CI 14.8-21.2] (n = 1,204,765) for CHIKV. Approximately 17.0% [95% CI 14.1-20.1] (n = 1,145,674) of Rio´s population had no contact with any of the three arboviruses. The reported cases of Zika, Dengue and Chikungunya by the current surveillance system in place is insufficient to estimate their real numbers, and our data indicate that Zika seroprevalence could be at least five times and Chikungunya 45 times bigger. The high number of individuals having never been infected by any of the three arboviruses, may indicate a proper scenario for future outbreaks.

Occurrence of domestic and intrusive triatomines (Hemiptera: Reduviidae) in sylvatic habitats of the temperate Monte Desert ecoregion of Argentina.

The eco-epidemiology of Triatominae and Trypanosoma cruzi transmission has been little studied in the Argentinean Monte ecoregion. Herein, we provide a comprehensive description of domestic and intrusive triatomines to evaluate the risk of reinfestation of rural dwellings. Triatoma infestans, T. patagonica, T. garciabesi and T. eratyrusiformis were collected by active searches or light traps. None were infected with T. cruzi. One T. infestans male was collected at 1.3 km from the nearest infested house. The finding of intrusive and domestic triatomines in sylvatic foci emphasizes the need of implementing an effective vector surveillance system.

Multiple Approaches to Address Potential Risk Factors of Chagas Disease Transmission in Northeastern Brazil.

Chagas disease is one of the most significant systemic parasitosis in Latin America, caused by Trypanosoma cruzi, which is mainly transmitted by hematophagous insects, the triatomines. This research was carried out in both domestic and wild environments throughout a Northeastern rural locality. Triatomines were captured in both peridomicile and wild environments, obtaining 508 specimens of triatomines, of which 99.6% were Triatoma brasiliensis. Insects were captured in 10 (18.5%) peridomiciles with an average of 8.3 triatomines per residence. Triatoma brasiliensis nymphs and adults were found in six peridomiciles, generating a 11.1% colonization. No T. cruzi infection was detected in the 447 peridomestic insects analyzed. On the other hand, of the 55 sylvatic T. brasiliensis molecularly examined for T. cruzi, 12 (21%) were positive, all harboring T. cruzi I. The blood meal analysis by enzyme-linked immunosorbent assay from gut content revealed that both peridomestic and wild triatomine populations fed mainly on birds, refractory to the parasite, which may explain the null rate of natural infection prevalence in the domestic environment. However, infected triatomines for potential home infestation within the radius of insect dispersion capacity were registered in rock outcrops around the dwellings. Anthropogenic environmental influences are able to rapidly alter these scenarios. Therefore, to avoid disease transmission to humans, we recommend constant vector control combined with periodic serological surveillance. The associated methodology presented herein may serve as a model for early detections of risk factors for Chagas disease transmission in the Brazilian Northeast.

Ecological aspects of Phlebotomines (Diptera: Psychodidae) and the transmission of American cutaneous leishmaniasis agents in an Amazonian/ Guianan bordering area.

BACKGROUND: An entomological study was conducted in the municipality of Oiapoque (lower Oyapock River Basin) in the Brazilian side bordering French Guiana to gain information on the transmission pattern of American cutaneous leishmaniasis (ACL) in that region, presumed to reflect the classical Amazonian/Guianan enzootic scenario. METHODS: Three ecologically isolated forested areas near urban environments were surveyed during the rainy and dry seasons of 2015 and 2016, using a multi-trapping approach comprising ground-level and canopy light traps, black and white colored cloth Shannon traps and manual aspiration on tree bases. Female phlebotomines were dissected to find infections and isolate flagellates from Leishmania spp. The strains were characterized by restriction fragment length polymorphism analysis and compared with those of local ACL cases and World Health Organization reference strains. RESULTS: Nyssomyia umbratilis, Trichopygomyia trichopyga and Evandromyia infraspinosa were the most frequently found species. Findings on relative abundance, spatiotemporal vector/ACL congruence, natural infections and anthropophilic insights strengthened the Guianan classical transmission of Leishmania (Viannia) guyanensis by Ny. umbratilis and suggested further investigations for Ev. infraspinosa. Nyssomyia umbratilis showed an eclectic feeding habit, including bird blood. Ecological data and literature reports also included Psychodopygus squamiventris maripaensis and Bichromomyia flaviscutellata on the list of suspected vectors. CONCLUSIONS: These findings contributed to understanding ACL ecoepidemiology in the Amazonian/Guianan scenario. Local studies are required to better comprehend the Leishmania spp. enzootic mosaic in specific ecotopes.

IDENTIFICATION OF SANDFLIES (Diptera: Psychodidae: Phlebotominae) BLOOD MEALS IN AN ENDEMIC LEISHMANIASIS AREA IN BRAZIL.

The aim of this study was to identify blood meals of female sandflies captured in the municipality of Governador Valadares, an endemic area of visceral and cutaneous leishmaniasis, in the State of Minas Gerais, Brazil. From May 2011 to January 2012, captures were performed using HP light traps in four districts. There were 2,614 specimens (2,090 males and 524 females) captured; 97 engorged females were identified belonging to the species Lutzomyia longipalpis(82.1%) and Lutzomyia cortelezzii(17.9%). Considering simple and mixed feeding, the enzyme-linked immunosorbent assay revealed a predominance of chicken blood (43.6%) in Lutzomyia longipalpis, showing the important role that chickens exert around the residential areas of Governador Valadares. This finding increases the chances of sandflies contact with other vertebrates and consequently the risk of leishmaniasis transmission.

Identification of sandflies (Diptera: Psychodidae: Phlebotominae) blood meals in an endemic Leishmaniasis area in Brazil / Identificação do repasto sanguíneo de flebotomíneos (Diptera: Psychodidae: Phlebotominae) provenientes de área endêmica de Leishmaniose no Brasil

SUMMARYThe aim of this study was to identify blood meals of female sandflies captured in the municipality of Governador Valadares, an endemic area of visceral and cutaneous leishmaniasis, in the State of Minas Gerais, Brazil. From May 2011 to January 2012, captures were performed using HP light traps in four districts. There were 2,614 specimens (2,090 males and 524 females) captured; 97 engorged females were identified belonging to the species Lutzomyia longipalpis(82.1%) and Lutzomyia cortelezzii(17.9%). Considering simple and mixed feeding, the enzyme-linked immunosorbent assay revealed a predominance of chicken blood (43.6%) in Lutzomyia longipalpis, showing the important role that chickens exert around the residential areas of Governador Valadares. This finding increases the chances of sandflies contact with other vertebrates and consequently the risk of leishmaniasis transmission.

RESUMOO objetivo deste estudo foi identificar o repasto sanguíneo de fêmeas de flebotomíneos capturadas no município de Governador Valadares, área endêmica de leishmaniose visceral e tegumentar no Estado de Minas Gerais, Brasil. Entre maio de 2011 e janeiro 2012 foram realizadas capturas com armadilhas luminosas HP em quatro bairros. Foram capturados 2.614 exemplares (2.090 machos e 524 fêmeas). Noventa e sete fêmeas ingurgitadas foram identificadas como pertencentes às espécies Lutzomyia longipalpis(82,1%) e Lutzomyia cortelezzii(17,9%). Considerando a alimentação simples e a mista, o ensaio imunoenzimático revelou em Lutzomyia longipalpisuma predominância de sangue de galinhas (43,6%), mostrando o importante papel que galinhas podem exercer no peridomicílio, aumentando a chance de contato dos flebotomíneos com outros vertebrados e, consequentemente, o risco de transmissão da leishmaniose.

Phlebotomine fauna, natural infection rate and feeding habits of Lutzomyia cruzi in Jaciara, state of Mato Grosso, Brazil.

Visceral leishmaniasis (VL) in Brazil is transmitted by the phlebotomine Lutzomyia longipalpis and in some midwestern regions by Lutzomyia cruzi. Studies of the phlebotomine fauna, feeding habits and natural infection rate by Leishmania contribute to increased understanding of the epidemiological chain of leishmaniases and their vectorial capacity. Collections were performed in Jaciara, state of Mato Grosso from 2010-2013, during which time 2,011 phlebotomines (23 species) were captured (68.70% Lu. cruzi and 20.52% Lutzomyia whitmani). Lu. cruzi females were identified by observing the shapes of the cibarium (a portion of the mouthpart) and spermatheca, from which samples were obtained for polymerase chain reaction to determine the rates of natural infection. Engorged phlebotomines were assessed to identify the blood-meal host by ELISA. A moderate correlation was discovered between the number of Lu. cruzi and the temperature and the minimum rate of infection was 6.10%. Twenty-two females were reactive to the antisera of bird (28%), dog (3.30%) and skunk (1.60%). We conclude that Lu. cruzi and Lu. whitmani have adapted to the urban environment in this region and that Lu. cruzi is the most likely vector of VL in Jaciara. Moreover, maintenance of Leishmania in the environment is likely aided by the presence of birds and domestic and synanthropic animals.

Phlebotomine fauna, natural infection rate and feeding habits of Lutzomyia cruzi in Jaciara, state of Mato Grosso, Brazil

Visceral leishmaniasis (VL) in Brazil is transmitted by the phlebotomine Lutzomyia longipalpis and in some midwestern regions by Lutzomyia cruzi. Studies of the phlebotomine fauna, feeding habits and natural infection rate by Leishmania contribute to increased understanding of the epidemiological chain of leishmaniases and their vectorial capacity. Collections were performed in Jaciara, state of Mato Grosso from 2010-2013, during which time 2,011 phlebotomines (23 species) were captured (68.70% Lu. cruzi and 20.52% Lutzomyia whitmani). Lu. cruzi females were identified by observing the shapes of the cibarium (a portion of the mouthpart) and spermatheca, from which samples were obtained for polymerase chain reaction to determine the rates of natural infection. Engorged phlebotomines were assessed to identify the blood-meal host by ELISA. A moderate correlation was discovered between the number of Lu. cruzi and the temperature and the minimum rate of infection was 6.10%. Twenty-two females were reactive to the antisera of bird (28%), dog (3.30%) and skunk (1.60%). We conclude that Lu. cruzi and Lu. whitmani have adapted to the urban environment in this region and that Lu. cruzi is the most likely vector of VL in Jaciara. Moreover, maintenance of Leishmania in the environment is likely aided by the presence of birds and domestic and synanthropic animals.

Correlation between populations of Rhodnius and presence of palm trees as risk factors for the emergence of Chagas disease in Amazon region, Brazil.

Among the states that comprise the legally defined Amazon region of Brazil, Pará has presented the highest occurrences of acute cases of Chagas disease over the last two decades. These cases have been attributed to consumption of fruits from native palm trees. In surveys in rural and wild areas of the municipality of Oriximiná, Pará, triatomine fauna, their main ecotopes and the infection rate due to Trypanosoma cruzi were identified using active and passive search methods: manual capture and Noireau traps, respectively. A total of 582 ecotopes were surveyed using 1496 Noireau traps. Out of 442 specimens collected, 289 were identified as Rhodnius robustus and 153 as Rhodnius pictipes. The infection rate caused by T. cruzi was 17.4%. The food sources of the triatomines were found to be birds, hemolymph, horses, and rodents. The association between R. robustus and inajá palm trees (Attalea marita), which are abundant in rural areas, was confirmed. On the other hand, R. pictipes is found in several palm tree species, such as inajá (A. marita), mucajá (Acrocomia aculeata), murumuru (Astrocaryum murumuru) and patauá (Oenocarpus bataua), and in bromeliads in wild areas. These occurrences of triatomine species in regions with or without T. cruzi infection, in the vicinity of the main settlement of the municipality, suggest that there is a need for entomological and epidemiological surveillance in this region.

Parasites in stool samples in the environment of Ilha da Marambaia, Rio de Janeiro, Brazil: an approach in public health.

This research aimed to describe the frequency of parasites in stool samples in the environment of Ilha da Marambaia, Rio de Janeiro, Brazil. One hundred and five stool samples were collected and processed by the coproparasitological techniques ethyl acetate sedimentation and centrifuge-flotation using saturated sugar solution. Parasites were detected in 81.9% of the samples, hookworm being the most prevalent, followed by Trichuris vulpis. Ascaris sp. eggs were also found. A high level of evolutive forms of parasites with public health risk was found in stool samples of the environment studied. We propose that health education programs, allied to an improvement of human and animal health care, must be employed to reduce the environmental contamination.

Parasites in stool samples in the environment of Ilha da Marambaia, Rio de Janeiro, Brazil: an approach in public health / Parasitos em amostras fecais de ambiente da Ilha da Marambaia, Rio de Janeiro, Brasil: uma abordagem em saúde pública

This research aimed to describe the frequency of parasites in stool samples in the environment of Ilha da Marambaia, Rio de Janeiro, Brazil. One hundred and five stool samples were collected and processed by the coproparasitological techniques ethyl acetate sedimentation and centrifuge-flotation using saturated sugar solution. Parasites were detected in 81.9% of the samples, hookworm being the most prevalent, followed by Trichuris vulpis. Ascaris sp. eggs were also found. A high level of evolutive forms of parasites with public health risk was found in stool samples of the environment studied. We propose that health education programs, allied to an improvement of human and animal health care, must be employed to reduce the environmental contamination.

O objetivo deste estudo foi descrever a frequência de parasitos em amostras fecais coletadas no ambiente da Ilha da Marambaia, Rio de Janeiro, Brasil. Cento e cinco amostras foram coletadas e processadas pelas técnicas coproparasitológicas de sedimentação em acetato de etila e centrifugo-flutuação em solução saturada de sacarose. Foi observada positividade em 81.9% das amostras, sendo ancilostomídeo o parasito mais frequente, seguido de Trichuris vulpis. Ovos de Ascaris sp. também foram detectados. Observou-se elevada frequência de parasitos com importância em saúde pública nas fezes recolhidas no ambiente. Programas de educação em saúde, aliados a atenção dos serviços das saúdes humana e animal, devem ser empregados para redução dos níveis de contaminação ambiental.

Studies on the Feeding Habits of Lutzomyia (Lutzomyia) longipalpis (Lutz & Neiva, 1912) (Diptera: Psychodidae: Phlebotominae) Populations from Endemic Areas of American Visceral Leishmaniasis in Northeastern Brazil.

The aim of this study was to identify potential blood feeding sources of L. (L.) longipalpis specimens from populations in Northeastern Brazil, endemic areas of American Visceral Leishmaniasis (AVL) and its correlation with the transmission of L. (L.) i. chagasi. The ELISA technique was applied using bird, dog, goat, opossum, equine, feline, human, sheep, and rodent antisera to analyze 609 females, resulting in an overall positivity of 60%. In all municipalities, females showed higher positivity for bird followed by dog antiserum and sand fly specimens were also positive for equine, feline, human, sheep, goat, opossum, and rodent antisera. The finding for 17 combinations of two or three types of blood in some females corroborates the opportunistic habit of this sand fly species. The results demonstrating the association between L. (L.) longipalpis and opossum suggest the need for further evaluation of the real role of this synanthropic mammal in the eco-epidemiology of AVL.

Ecology of Triatoma brasiliensis in northeastern Brazil: seasonal distribution, feeding resources, and Trypanosoma cruzi infection in a sylvatic population.

We assessed some ecological parameters of Triatoma brasiliensis in rock piles in the state of Ceará during the rainy and dry seasons. The greatest density was in April (median = 12.5 triatomines/site). The greatest abundance was in December, when the insects were more dispersed and the density per site was lower (6 triatomines/site). The nutritional status of females and 5th instar nymphs was increased in July. The rate of T. cruzi infection reached its highest peak in July (10.9%). ELISA revealed that the principal food sources were birds (33.1%), followed by armadillos (18.8%). Food sources were more frequently identified during the rainy season. T. brasiliensis specimens collected in the drought tended to: i) present lower rates of T. cruzi infection and gut content reactivity to tested antisera, ii) have a poorer nutritional status, iii) exhibit lower fecundity, iv) be more dispersed among the studied collection sites, and v) be more abundant and easily collected in the surface of the rocks, possibly reflecting an increased searching for blood meals. Such findings underscore epidemiological concerns and allow inferences about the season when triatomines can more frequently invade the peridomestic environment in search of food and recolonize artificial structures.

Risk presented by Copernicia prunifera palm trees in the Rhodnius nasutus distribution in a Chagas disease-endemic area of the Brazilian northeast.

With the aid of live-bait traps, we studied the risk that Copernicia prunifera palm trees, present in both periurban and rural localities of an endemic Brazilian northeast Chagas disease region, represent to domestic infestation by Rhodnius nasutus. In this area, this important vector has been encountered harboring and transmitting Trypanosoma cruzi, the etiologic agent of the American trypanosomiasis, to mammals, possibly including humans. Results indicate that this bug colonizes C. prunifera palm trees of both regions, mainly in dry seasons, and is infected with high levels of T. cruzi. Although more triatomines were captured in rural areas, proportionally the number of infected bugs from peri-urban regions was much higher. Herein we address the epidemiologic implications and challenge for the Brazilian health authorities to control the disease in this region, where the native palm trees have been largely destroyed causing a severe disturbance in the environmental equilibrium.

Attraction of mosquitoes to domestic cats in a heartworm enzootic region.

Heartworm disease is caused by a mosquito-borne parasite that can affect many different mammalian species and has worldwide distribution. The agent, Dirofilaria immitis (Leidy 1856), infect mainly dogs but feline infection have been frequently reported in the last decade. Feline heartworm infection is difficult to detect, therefore, low reported prevalence could reflect true low prevalence or poor diagnostic efficiency. As mosquitoes are known to be attracted differently by different mammalian species, mosquitoes were collected from both a cattery and a contiguous home located in a canine heartworm enzootic area in Niterói, state of Rio de Janeiro, Brazil. For 14 months, mosquitoes were collected weekly for genus identification, speciation when possible, and for individual blood meal identification. Culex species mosquitoes were the most captured and those most frequently found with feline blood meal, followed by Aedes species that, although captured in lower numbers, also fed on feline blood. While Culex species mosquitoes have been reported as potential secondary heartworm vectors for dogs and primary vectors for cats, the present results suggest that Aedes species mosquitoes may also be involved in feline heartworm transmission in a larger proportion than previously thought.

Feeding sources and natural infection of Belminus herreri (Hemiptera, Reduviidae, Triatominae) from dwellings in Cesar, Colombia.

Belminus herreri, originally described from specimens collected in Panama, was considered entirely silvatic until to 2000 when it was found for the first time in a domestic habitat in Colombia. In 2001, during a new search of houses in the Department of Cesar, Colombia, 121 specimens were collected. Study of their feeding sources using an ELISA test revealed that 96% of these specimens had fed on cockroaches (Blattidae). However, a small proportion of these B. herreri specimens also showed the presence of Trypanosoma cruzi in their gut contents, suggesting a possible role for these insects in the epidemiology of Chagas disease.

Feeding sources and natural infection of Belminus herreri (Hemiptera, Reduviidae, Triatominae) from dwellings in Cesar, Colombia

Belminus herreri, originally described from specimens collected in Panama, was considered entirely silvatic until to 2000 when it was found for the first time in a domestic habitat in Colombia. In 2001, during a new search of houses in the Department of Cesar, Colombia, 121 specimens were collected. Study of their feeding sources using an ELISA test revealed that 96 percent of these specimens had fed on cockroaches (Blattidae). However, a small proportion of these B. herreri specimens also showed the presence of Trypanosoma cruzi in their gut contents, suggesting a possible role for these insects in the epidemiology of Chagas disease.

Leishmaniose tegumentar canina em Morada das Aguias (Serra da Tiririca), Maricá, Rio de Janeiro, Brasil / Canine tegumentary leishmaniasis in Morada das Aguias (Serra da Tiririca), Maricá, Rio de Janeiro, Brazil

Descreve-se a ocorrência da leishmaniose tegumentar em cães da localidade de Morada das Aguias (Serra da Tiririca), Maricá, Estado do Rio de Janeiro, Brasil. Foram avaliados 83 cães por meio de exames clínico, sorológico e parasitológico. Os soros de 11 (13,2 por cento) animais foram reagentes à imunofluorescência indireta (IFI) e de 30 (36,1 por cento) ao ensaio imunoenzimático (ELISA). Ulceras cutâneas e ou mucosas foram observadas em 18 (n = 83; 21,7 por cento) dos animais. Leishmania foi isolada de 11 cães. Discute-se a ocorrência da doença e a ocupação da localidade.

[Leishmania (Viannia) braziliensis in naturally infected dogs]. / Leishmania (Viannia) braziliensis em cães naturalmente infectados.

Eight dogs from Maricá Municipality (RJ), with suggestive lesion of American tegumentary leishmaniasis were studied by parasitological and serological methods. Leishmania spp was found in six dogs by in vitro cultivation. Specific antibodies were detected in six dogs by ELISA and in two by indirect immunofluorescence. Five canine isolates were found to belong to the same zymodeme as Leishmania (Viannia) braziliensis. The authors suggest that clinically suspect dogs should be followed-up in an attempt to confirm the diagnostic of canine tegumentary leishmaniasis.

Leishmania (Viannia) braziliensis em cäes naturalmente infectados / Leishmania (Viannia) braziliensis in naturally infected dogs

Foram estudados oito cäes provenientes do Município de Maricá (RJ), com lesöes sugestivas de leishmaniose tegumentar americana por métodos parasitológicos e sorológicos. Leishmania spp foi encontrada em seis cäes através do cultivo in vitro. Anticorpos específicos foram detectados em seis animais pelo ELISA e em dois pela imunofluorescência indireta. Cinco isolados caninos analisados apresentaram zimodema similar a Leishmania (Viannia) braziliensis. Sugere-se que cäes clinicamente suspeitos sejam acompanhados periodicamente, na tentativa de confirmar o diagnóstico da leishmaniose tegumentar canina