Maria de Fátima Freire de Melo Ximenes

Zika virus in Brazil and the danger of infestation by Aedes (Stegomyia) mosquitoes

Zika virus, already widely distributed in Africa and Asia, was recently reported in two Northeastern Brazilian: State of Bahia and State of Rio Grande do Norte, and one Southeastern: State of São Paulo. This finding adds a potentially noxious virus to a list of several other viruses that are widely transmitted by Aedes (Stegomyia) aegypti and Aedes (Stegomyia) albopictus in Brazil. The pathology and epidemiology, including the distribution and vectors associated with Zika virus, are reviewed. This review is focused on viruses transmitted by Aedes (Stegomyia) mosquitoes, including dengue, Chikungunya, Zika, Mayaro, and yellow fever virus, to emphasize the risks of occurrence for these arboviruses in Brazil and neighboring countries. Other species of Aedes (Stegomyia) are discussed, emphasizing their involvement in arbovirus transmission and the possibility of adaptation to environments modified by human activities and introduction in Brazil.

An Emerging Peri-Urban Pattern of Infection with Leishmania chagasi, the Protozoan Causing Visceral Leishmaniasis in Northeast Brazil

Peri-urban visceral leishmaniasis (VL) caused by Leishmania chagasi is emerging in a new epidemiologic pattern in Brazilian cities. We studied peri-urban VL in endemic neighborhoods surrounding Natal, Brazil, identified through hospitalized individuals with VL. Clinical and environmental information obtained for 1106 members of 216 families living in endemic neighborhoods enabled us to identify 4 groups: VL: individuals with current or prior symptomatic visceral leishmaniasis (n=135); DTH+: individuals with positive delayed-type hypersensitivity response with no history of VL (n=390); Ab+: individuals with negative DTH response and seropositive (n=21); DTH−: individuals with negative DTH and seronegative (n=560). The mean±SD age of VL was 9.3±12.3 y. The gender distribution was nearly equal below age 5, but skewed toward males at higher ages. Acutely infected VL subjects had significantly lower hematocrits, neutrophils, and eosinophils than other categories. AB+ subjects also had lower eosinophil counts than others, a possible immune marker of early infection. VL was not associated with ownership of dogs or other animals, raising the question whether the reservoir differs in peri-urban settings. This new pattern of L. chagasi infection enables us to identify epidemiological and host factors underlying this emerging infectious disease.

Density of Sand Flies (Diptera: Psychodidae) in Domestic and Wild Animal Shelters in an Area of Visceral Leishmaniasis in the State of Rio Grande do Norte, Brazil

The objective of the present study was to determine the association of sand flies with the presence of domestic and wild animals in the peridomiciliary area. The sand flies were collected using direct aspiration and CDC light traps placed in animal shelters. The results suggest that different sand flies species have different behavioral characteristics in an apparent preference for animal baits and that Lutzomyia longipalpis and Lu. evandroi were the most eclectic species regarding their biotope choice. Lu. longipalpis showed a distinct preference for horses and Lu. evandroi for armadillos.

Flebotomíneos (Diptera: Psychodidae) e leishmanioses no Rio Grande do Norte, Nordeste do Brasil: reflexos do ambiente antrópico

Natural environmental changes or those resulting from anthropic factors and their impact on infectious diseases have been evaluated in several studies. The objective of this work was to analyze the correlation between the anthropic environment, phlebotomine and leishmaniases in Rio Grande do Norte State, in Northeast Brazil. Information relative to the distribution of vector species in visceral and tegumentary leishmaniasis areas was associated to the record of cases notified by Public Health organs. The analysis suggests associations between the vector species and distribution of the disease with demographic and physionomic characteristics, disorderly growth in the metropolitan area, living conditions and environmental degradation of the Eastern Littoral, the principal area of notified visceral leishmaniasis cases.

Canine visceral leishmaniasis in urban and rural areas of Northeast Brazil

The purpose of this study was to determine the clinical and laboratory profiles of canine leishmaniasis in two distinct areas. Dogs from urban and rural areas were examined. The population studied in the metropolitan area included 54 dogs. Of these, 20 (37%) animals did not present with any signs suggestive of visceral leishmaniasis (VL). Among these, only eight were confirmed negative by ELISA (rK39 and CE) and 12 dogs, clinically negative for leishmaniasis, were seropositive by ELISA (rK39 and CE). Thinness, conjunctivitis and onychogryphosis were the most frequent clinical signs in the urban areas, followed by crusty lesions, alopecia, ulcerated lesions, hyperkeratosis and exfoliation. In the metropolitan area human VL cases occurred mainly in 1991, 1992, 1999 and 2000. In the rural areas the ELISA rK39 test detected a seroprevalence of 11.3% and ELISA CE (Leishmania crude extract) of 20.6%. Thirty-nine dogs were examined 6 months after the first visit. Serological exams using rK39 antigen showed seroconversion of only one dog, whereas Leishmania CE showed seroconversion of 13 (33.4%) dogs. In this rural environment 83.3% of the positive dogs were asymptomatic. Lutzomyia intermedia and Lu. longipalpis were the most predominant sandfly vector species. Amastigotes were identified in spleen and liver fragments of symptomatic necropsied animals. PCR amplification of DNA isolated from promastigote culture indicated that the species was Leishmania chagasi. This finding suggests that delayed diagnosis and euthanasia of potentially infectious animals may occur with an increased transmission risk to sandflies and subsequently to humans.

Effect of abiotic factors on seasonal population dynamics of Lutzomyia longipalpis (Diptera: Psychodidae) in northeastern Brazil.

Abstract The resurgence of visceral leishmaniasis in Brazil increases the need for studies to elucidate the spatial and temporal dynamics of Lutzomyia longipalpis (Lutz & Neiva) (Diptera: Psychodidae), the vector of Leishmania infantum, the causative agent of visceral leishmaniasis in Brazil. Sand flies were captured in peridomestic habitats biweekly for 3 yr. Cross-correlation tests and spectral analysis were used to analyze the simultaneous and lag-time correlations between Lu. longipalpis population densities and abiotic factors of temperature, relative humidity, wind velocity, and rainfall. Distinct seasonal patterns were observed for males and females, with intervals of 6 mo between population peaks for males and 12 mo for females. Peak female population densities lagged 3 mo behind the maximum annual temperature. Female population density was negatively correlated with relative humidity. An increase in average wind velocity was followed by a decrease in the number of females for 2 wk. Understanding the relationship between the seasonal population dynamics of Lu. longipalpis and abiotic factors will contribute to the design of better control measures to decrease transmission of L. infantum and consequently the incidence of leishmaniasis.

Distribution of Phlebotomine Sand Flies (Diptera: Psychodidae) in the State of Rio Grande do Norte, Brazil

Abstract Visceral and cutaneous leishmaniasis are major endemic diseases in northeast Brazil. The objective of the current study was to determine the species and geographic distribution of potential sand fly vectors of Leishmania in the state of Rio Grande do Norte. Sand flies were captured using CDC light traps in 30 municipalities distributed throughout the 8 geographic zones of the state. Twelve Lutzomyia species were identified. Lutzomyia longipalpis Lutz & Neiva was the most prevalent and accounted for 85.59% of the sand fly captured. The remaining species were distributed as follows: L. evandroi Costa Lima & Antunes (10.83%), L. oswaldoi Mangabeira (0.99%), L. sallesi Galvão & Coutinho (0.58%), L. intermedia Lutz & Neiva (0.53%), L. lenti Mangabeira (0.53%), L. migonei França (0.49%), L. walkeri Newstead (0.24%), L. goiana Martins, Falcão & Silva (0.15%), L. samueli Deane (0.04%), and L. capixaba Dias, Falcão, Silva & Martins (0.03%), and L. peresi Mangabeira (0.01%). L. longipalpis, which is known to be a vector of Leishmania chagasi Cunha & Chagas (L. donovani chagasi), was captured in 93% of municipalities distributed across all geographical areas of the state and its distribution was independent of obvious climatic and topographic parameters. It was identified in all municipalities where human visceral leishmaniasis had been reported. In contrast, climate and topography appeared to be important for other Lutzomyia species. For example, L. intermedia and L. migonei, which are known to transmit Leishmania braziliensis Viana, were geographically restricted. They were captured in municipalities where cases of cutaneous and mucosal leishmaniasis had been reported. The widespread distribution of L. longipalpis, its adaptation to peridomicillary settings, and its ability to transmit L. (d.) chagasi suggest that a large number of persons may be at risk of acquiring visceral leishmaniasis in the state of Rio Grande do Norte, Brazil.

Forum: geographic spread and urbanization of visceral leishmaniasis in Brazil. Postscript: new challenges in the epidemiology of Leishmania chagasi infection

as an example of this process in Brazil, was similar to that observed in the Northeast, with subsequent spread to other cities in the South-east and Central-West. It is worrisome that these endemic areas have a high population density, thus placing the population at increased risk of infection.Dogs have traditionally been considered the principal reservoirs of

Characteristics of the Biological Cycle of Lutzomyia evandroi Costa Lima & Antunes, 1936 (Diptera: Psychodidae) under Experimental Conditions

Lutzomyia evandroi Costa Lima and Antunes, 1936 is found in Rio Grande do Norte, northeastern Brazil, in areas of visceral and mucocutaneous leishmaniasis and follows the same geographic distribution of L. longipalpis. The biological cycle, oviposition, morphological and behavioral characteristics of the species were studied under experimental conditions. The average number of eggs per wild caught female varied from 21 to 50 eggs along the year, with a peak occurring between January and March and another in August, with oviposition lasting for 4 to 12 days. The mean larval phase was 24 days. Ovipositing rates were influenced by rainfall and temperature indexes, with an increase of eggs per oviposition at the beginning and at the end of the rainy season, and a decrease at the peak of the rainy season.

Feeding Preferences of Lutzomyia longipalpis (Diptera: Psychodidae), the Sand Fly Vector, for Leishmania infantum (Kinetoplastida: Trypanosomatidae)

ABSTRACT Leishmania infantum, the causative agent of visceral leishmaniasis (VL) in Brazil, is spread mostly by the bite of the sand fly Lutzomyia longipalpis (Lutz & Neiva). We trapped sand flies in endemic neighborhoods near Natal, Brazil, where cases of human and dog VL were documented. Amplification of species-specific cytochrome b (Cyt b) genes by polymerase chain reaction revealed that sand flies from rural and periurban areas harbored blood from different sources. The most common source of bloodmeal was human, but blood from dog, chicken, and armadillo was also present. We tested the preference for a source of bloodmeal experimentally by feeding L. longipalpis F1 with blood from different animals. There were significant differences between the proportion of flies engorged and number of eggs laid among flies fed on different sources, varying from 8.4 to 19 (P < 0.0001). Blood from guinea pig or horse was best to support sand fly oviposition, but human blood also supported sand fly oviposition well. No sand flies fed on cats, and sand flies feeding on the opossum Monodelphis domestica Wagner produced no eggs. These data support the hypothesis that L. longipalpis is an eclectic feeder, and humans are an important source of blood for this sand fly species in periurban areas of Brazil.