José W. Queiroz

Geographic information systems and applied spatial statistics are efficient tools to study Hansen's disease (leprosy) and to determine areas of greater risk of disease

Applied Spatial Statistics used in conjunction with geographic information systems (GIS) provide an efficient tool for the surveillance of diseases. Here, using these tools we analyzed the spatial distribution of Hansens disease in an endemic area in Brazil. A sample of 808 selected from a universe of 1,293 cases was geocoded in Mossoró, Rio Grande do Norte, Brazil. Hansens disease cases were not distributed randomly within the neighborhoods, with higher detection rates found in more populated districts. Cluster analysis identified two areas of high risk, one with a relative risk of 5.9 (P = 0.001) and the other 6.5 (P = 0.001). A significant relationship between the geographic distribution of disease and the social economic variables indicative of poverty was observed. Our study shows that the combination of GIS and spatial analysis can identify clustering of transmissible disease, such as Hansens disease, pointing to areas where intervention efforts can be targeted to control disease.

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.

The emergence of concurrent HIV-1/AIDS and visceral leishmaniasis in Northeast Brazil

HIV has become increasingly prevalent in the Northeast region of Brazil where Leishmania infantum chagasi is endemic, and concurrent AIDS and visceral leishmaniasis (VL) has emerged. In this study, persons with HIV/AIDS and VL (n=17) had a mean age of 37.3 years (range 29-53 years) compared with 12.5 years (1-80 years) for persons with VL alone (n=2836). Males accounted for 88% of cases with concurrent VL and AIDS and 65% of those with VL alone. The mean CD4 count and antileishmanial antibody titre were lower and recurrence of VL and death were more likely with co-infection. Considering the prevalences of L.i. chagasi and HIV in the region, this may herald the emergence of an important public health problem.

Leishmania infantum chagasi in Northeastern Brazil: Asymptomatic Infection at the Urban Perimeter

Visceral leishmaniasis (VL) is endemic in large cities in Brazil, including Natal. We determined the prevalence of asymptomatic human infection with Leishmania infantum chagasi and associated environmental risks around Natal. Infection was detected by Leishmania skin test (LST) and anti-leishmanial antibodies in humans and anti-leishmanial antibodies in dogs. Amongst 345 humans, 24.6% were seropositive, and 38.6% were LST-positive. Prevalence of positive serology was similar in both sexes and across all ages. However, positive LST responses increased with age, suggesting that LST is long-lasting and cumulative. Multinomial logistic analysis showed that LST response varied with location (P = 0.007) and that males were more frequently LST-positive (P = 0.027). Indicators of lower socioeconomic status associated significantly with human infection. Furthermore, there was geographic coincidence of seropositive humans and dogs (r = 0.7926, P = 0.011). These data suggest that dog and human L. i. chagasi infection are intimately interrelated in environmental conditions associated with low income.

Active Surveillance of Hansen's Disease (Leprosy): Importance for Case Finding among Extra-domiciliary Contacts

Hansens disease (leprosy) remains an important health problem in Brazil, where 34,894 new cases were diagnosed in 2010, corresponding to 15.3% of the worlds new cases detected in that year. The purpose of this study was to use home visits as a tool for surveillance of Hansens disease in a hyperendemic area in Brazil. A total of 258 residences were visited with 719 individuals examined. Of these, 82 individuals had had a previous history of Hansens disease, 209 were their household contacts and 428 lived in neighboring residences. Fifteen new Hansens disease cases were confirmed, yielding a detection rate of 2.0% of people examined. There was no difference in the detection rate between household and neighbor contacts (p = 0.615). The two groups had the same background in relation to education (p = 0.510), household income (p = 0.582), and the number of people living in the residence (p = 0.188). Spatial analysis showed clustering of newly diagnosed cases and association with residential coordinates of previously diagnosed multibacillary cases. Active case finding is an important tool for Hansens disease control in hyperendemic areas, enabling earlier diagnosis, treatment, decrease in disability from Hansens disease and potentially less spread of Mycobacterium leprae.

Family history of hypertension as an important risk factor for the development of severe preeclampsia

Objective. To determine the risk of preeclampsia in a population with respect to maternal and sister histories of chronic hypertension, preeclampsia and eclampsia. Design. A case‐control study of severe preeclampsia. Setting. Maternity hospital in Natal, Brazil. Participants. A total of 412 subjects were enrolled, 148 cases and 264 controls. Main outcome measures. Personal and familial histories of hypertensive disorders. Odds ratio estimates of preeclampsia with respect to family history of hypertensive diseases. Results. Women with a history of hypertensive disorders were more frequent in the case group (p = 0.001). Women whose mothers had a history of hypertension (p = 0.003), preeclampsia (p = 0.007) or eclampsia (p = 0.038) were at increased risk of severe preeclampsia. The risk of preeclampsia was greater when the woman had a sister with a history of hypertension (OR 2.60, 95% CI 1.60–4.21, p < 0.001), preeclampsia (OR 2.33, 95% CI 1.58–3.45, p < 0.001), or eclampsia (OR 2.57, 95% CI 1.28–5.16, p = 0.008). The risk of preeclampsia was also higher for women who had both a mother and sister with a history of hypertension (OR 3.65, 95% CI 1.65–8.09, p = 0.001). Conclusions. A family history of hypertensive disorders increased the risk of eclampsia and hemolysis elevated liver enzymes and low platelet (HELLP) syndrome in a Brazilian population.

Leptospirosis in a subsistence farming community in Brazil

Leptospirosis has been reported in rural areas of Brazil. However, there is limited information about the exposure risk or the risk of Leptospira infection for rural-based populations. A cross-sectional study was carried out in order to determine the prevalence and risk factors for prior Leptospira infection in a rural subsistence farming region of the state of Rio Grande do Norte, an area in which outbreaks of leptospirosis have occurred. Among 290 individuals enrolled, 44 (15.2%) had anti-Leptospira IgM antibodies as determined by IgM ELISA. Infection tended to occur with activities related to the rice fields (P=0.08). Our findings indicate that Leptospira infection occurs even in years of low rainfall, and may have an important impact among poor rural-based subsistence farmers in Brazil. Additional studies are needed to characterize the mode of transmission in this region.

Association of Pro-Inflammatory Cytokines and Iron Regulatory Protein 2 (IRP2) with Leishmania Burden in Canine Visceral Leishmaniasis

Leishmania infantum infection in humans and dogs can evolve with a wide range of clinical presentations, varying from asymptomatic infections to visceral leishmaniasis. We hypothesized that the immune response elicited by L. infantum infection could modulate whether the host will remain asymptomatic or progress to disease. A total of 44 dogs naturally infected with L. infantum were studied. Leishmania burden was estimated in the blood and spleen by qPCR. The expression of IFN-γ, TNF-α, IL-10 and Iron Regulatory Protein 2 (IRP2) were determined in the spleen by quantitative PCR. Sera cytokines were evaluated by ELISA. Dogs were grouped in quartiles according parasite burden. Increased expression of IFN-γ and TNF-α was associated with reduced Leishmania burden, whereas increased IL-10 and IRP2 expressions were associated with higher Leishmania load. Increased plasma albumin and IFN-γ expression explained 22.8% of the decrease in parasite burden in the spleen. These data confirm that lower IFN-γ response and higher IL-10 correlated with increased parasite load and severity of the visceral leishmaniasis in dogs. The balance between the branches of immune response and the intracellular iron availability could determine, in part, the course of Leishmania infection.

Clinical characteristics of Guillain-Barré syndrome in a tropical country: a Brazilian experience.

Dourado ME, Félix RH, da Silva WKA, Queiroz JW, Jeronimo SMB. Clinical characteristics of Guillain–Barré syndrome in a tropical country: a Brazilian experience. 
Acta Neurol Scand: 2012: 125: 47–53. 
© 2011 John Wiley & Sons A/S.