Nilza Dutra Alves

Control of phlebotomine (Diptera: Psychodidae) leishmaniasis vectors

Phlebotomines are of medical and veterinary concern as they vector leishmaniasis, bartonellosis and some arboviruses. The adaptations of some species to places modified by humans bring these vectors into contact with dwellings, which can facilitate disease transmission, and the vector control strategies adopted have rendered controversial results. Regarding leishmaniasis, for instance, which vector and reservoirs control can be effective, there is an assumption that the incidence of human infection is directly related to the number of infectious dogs, as well as to entomological factors. Therefore, vector control can provide a cheaper and more practical solution to prevent cases of leishmaniasis. Nevertheless, due to the complexity of the factors involved, chemical control is still essential, and biological insecticides and insecticide plants, for example, represent areas for study that should be encouraged and developed since they show promising results. This paper summarizes the control strategies adopted so far, especially the methods and efficiency of the entomological components of leishmaniasis control programs.

Monitoring of Lutzomyia longipalpis Lutz & Neiva, 1912 in an area of intense transmission of visceral leishmaniasis in Rio Grande do Norte, Northeast Brazil

Urban increase of visceral leishmaniasis (VL) in Brazil is associated with the adaptation of its vector, Lutzomyia longipalpis, to environments modified by humans. The present study reports the results of an entomological monitoring of L. longipalpis and the effect of environmental variables on its population density. Sandflies were captured in the municipality of Mossoró, State of Rio Grande do Norte, Northeastern Brazil, from January 2005 to December 2006. Two CDC light traps were placed monthly for four consecutive nights in the peridomicile of selected households. Data analysis was based on the chi-square test and linear regression. A total of 2,087 sandflies were captured, 99.86% of which were L. longipalpis. A higher proportion of females were captured (p < 0.05). Monthly analysis of the variables temperature, relative humidity and rainfall did not show a significant influence on population density. However, there were seasonal differences: approximately 70% of sand flies were captured during the rainy season (p < 0.05). The predominant species, L. longipalpis, is present in substantial number, representing a public health risk. Therefore, because of higher prevalence during the rainy season, we recommend intensified VL control measures before and during this season to reduce the risk of disease transmission.

Sandflies (Psychodidae: Phlebotominae) survey in an urban transmission area of visceral leishmaniasis, Northeastern Brazil

Visceral leishmaniasis (VL) is a major public health challenge in Brazil, especially in states where it is endemic. The aim of this study was to investigate the relationship of sand fly population density with environmental variables (temperature, rainfall and relative humidity) in urban areas of the city of Mossoró, Rio Grande do Norte, Northeastern Brazil. Sand flies were captured with Center Disease Control (CDC) traps installed monthly in the intra and peridomicile of three houses. Data analysis was based on the chi-square test and linear regression. A total of 7,347 sand flies were captured, being 93.85% Lutzomyia longipalpis and 6.15% Lutzomyia evandroi. Sand flies were more commonly found in the peridomicile and there was no difference between the number of males and females. The variables rainy season as well as relative humidity and rainfall, alone or together, did not have an effect on sand fly population density. However, high temperatures had a negative effect. The study of the behavior of sand flies in specific units of endemic areas can provide input to public health authorities for planning appropriate VL vector control measures.

The effects of the fungus Metarhizium anisopliae var. acridum on different stages of Lutzomyia longipalpis (Diptera: Psychodidae)

The control of Visceral Leishmaniasis (VL) vector is often based on the application of chemical residual insecticide. However, this strategy has not been effective. The continuing search for an appropriate vector control may include the use of biological control. This study evaluates the effects of the fungus Metarhizium anisopliae var. acridum on Lutzomyia longipalpis. Five concentrations of the fungus were utilized, 1 x 10(4) to 1 x 10(8) conidia/ml, accompanied by controls. The unhatched eggs, larvae and dead adults previously exposed to fungi were sown to reisolate the fungi and analysis of parameters of growth. The fungus was subsequently identified by PCR and DNA sequencing. M. anisopliae var. acridum reduced egg hatching by 40%. The mortality of infected larvae was significant. The longevity of infected adults was lower than that of negative controls. The effects of fungal infection on the hatching of eggs laid by infected females were also significant. With respect to fungal growth parameters post-infection, only vegetative growth was not significantly higher than that of the fungi before infection. The revalidation of the identification of the reisolated fungus was confirmed post-passage only from adult insects. In terms of larvae mortality and the fecundity of infected females, the results were significant, proving that the main vector species of VL is susceptible to infection by this entomopathogenic fungus in the adult stage.

Abdominal Exploration in Captive Collared Peccaries (Tayassu tajacu) by Ultrasonography

This study determines the morphology and ultrasound features of the abdominal organs in male, nestling and healthy collared peccaries. The bladder wall is hyperechogenic, with a thickness of 0.2 ± 0.08 cm. The kidneys present a well‐defined cortex, medulla and pelvis, and the dimensions are 2.56 ± 0.3 × 4.6 ± 0.8 cm for the left and 2.51 ± 0.4 × 4.86 ± 1.1 cm for the right kidney. The spleen has a uniform echotexture over its entire surface. The largest dimensions of the liver are 2.0 ± 0.57 cm for the left lobe and 1.42 ± 0.66 cm for the caudate lobe. The liver presents a homogeneous echotexture in the majority of cases, but sometimes some hyperechoic spots are present. The stomach wall has a thickness of 0.42 ± 0.28 cm. The bowel loops show alternate hyperechoic and hypoechoic layers with a uniform diameter and a wall thickness of 0.19 ± 0.07 cm.

Knowledge of the Population about Visceral Leishmaniasis Transmission in Endemic Areas near the Banks of the Mossoró River in Northeastern Brazil

Visceral leishmaniasis (VL) is an anthropozoonosis with high prevalence and incidence in the Northeastern region of Brazil. This study aimed to determine whether people living near the Mossoró River in the city of Mossoró, Rio Grande do Norte, have knowledge of VL and to characterize the environmental properties of this region. Questionnaires were administered to 478 residents in three neighborhoods near the Mossoró River, addressing the population’s knowledge about VL and environmental characteristics. Most survey participants were female, with ages between 18 and 40 years, 53.8% had completed primary education, and 61.5% owned pet dogs (p < 0.05). The majority (95.9%) showed little knowledge about the characteristics inherent to sandflies, and 85.3% were unaware of the environments preferred by this vector (p < 0.05). Sewage from the homes of respondents was mainly dumped into the river (44.6%), and 76.6% of the respondents complained about the accumulation of garbage in the streets (p < 0.05). The association between education and knowledge about the transmission of VL and preferred vector locations was statistically significant (p < 0.05). The lack of knowledge in the population about VL and the residential environment indicates a risk of maintaining sand fly habitats and hence disease transmission.

Caracterização da microbiota auricular de cutias (Dasyprocta aguti) criadas em cativeiro

The aim of this study was to identify the aerobic bacteria of the auricular natural microbiota from healthy agoutis (Dasyprocta aguti Linnaeus, 1758). In the total, 48 agoutis were used in this experiment, being 32 adults and 16 puppies (both groups divided into equal parts between males and females). The animals were raised under captive conditions, in the Brazilian Semiarid. From each animal, a sample of auricular secretion was collected from each auricular pinna and processed for microbiological analyses. A total of 96 samples were collected and analyzed by colony macroscopic format, cytology and by biochemistry proofs with the objective of isolate and identify the microorganisms. The main bacteria found were Staphylococcus spp. (47.26%), Streptococcus spp. (12.80%), Bacillus spp. (22.73%) and Corynebacterium spp. (17.30%). As conclusion, the most frequent bacteria in auricular pinna of healthy agoutis are Gram-positive cocci and rods, similarly to found in some pets.