Changing demographics of visceral leishmaniasis in northeast Brazil: Lessons for the future

Background

Visceral leishmaniasis (VL) caused by Leishmania infantum became a disease of urban areas in Brazil in the last 30 years and there has been an increase in asymptomatic L. infantum infection with these areas.

Methodology/Principal findings

A retrospective study of human VL was performed in the state of Rio Grande do Norte, Brazil, for the period of 1990–2014. The data were divided into five-time periods. For all VL cases, data on sex, age, nutritional status and childhood vaccination were collected. Geographic information system tools and statistical models were used to analyze the dispersion of human VL. The mean annual incidence of VL was 4.6 cases/100,000 inhabitants, with total 3,252 cases reported. The lethality rate was 6.4%. Over time the annual incidence of VL decreased in the 0–4 years (p<0.0001) and 5–9 (p <0.0001) age groups, but increased in ages 20–39 (p<0.001) and >40 years (p<0.0001). VL occurred more often in males (β₂ = 2.5; p<0.0001). The decreased incidence of VL in children was associated with improved nutritional status and childhood immunizations including measles, poliomyelitis, BCG, and hepatitis B. Human VL correlated temporally and geographically with canine L. infantum infection (p = 0.002, R² = 0.438), with rainfall and with Lutzomyia longipalpis density (r = 0.762). Overall, the incidence of VL decreased, while VL-AIDS increased, especially between 2010–2014. VL was more frequently found in areas that lacked urban infrastructure, detected by lack of garbage collection and sewers, whereas HIV infection was associated with higher levels of schooling and evidence of higher socioeconomic status.

Conclusion/Significance

The demographics of VL in northeastern Brazil have changed. Disease incidence has decreased in children and increased in adults. They were associated with improvements in nutrition, socioeconomic status and immunization rates. Concurrent VL-AIDS poses a serious challenge for the future.

We studied factors associated with the changing demographics of visceral leishmaniasis (VL) in Northeast Brazil, including environmental and socioeconomic determinants of disease, during the period 1990 to 2014. The incidence of VL was higher in urban areas, and regions with higher levels of canine L. infantum infection. Human males were more commonly affected than females. The incidence of VL in children under age 10 decreased during the period of study, simultaneous with increased incidence in adults. Reduction in the VL incidence among children was associated with improved socioeconomic status, administration of childhood vaccines and better nutritional status. Geographic areas with higher rainfall had higher densities of Lu. longipalpis, the primary vector of L. infantum in Brazil. VL was more frequently found in areas with indicators of poverty including sparse garbage collection and lack of urban infrastructure. During the past 25 years, HIV/AIDS has spread to areas where VL is endemic and has contributed to an increased incidence of VL-AIDS co-infection in adults.

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.

Preeclampsia is associated with increased maternal body weight in a northeastern Brazilian population

Background

Preeclampsia is a disease with great variability in incidence across the world. The mortality is higher in lower income countries, where it is the leading cause of maternal mortality. This study aimed to determine the frequency of and risk factors for preeclampsia in a low income population from an urban area of Brazil.

Methods

A prospective case control study of 242 women of which 30 developed preeclampsia, 4 had gestational hypertension, 2 had superimposed hypertension, 11 had spontaneous abortion, 13 were lost to follow up and 192 had normal pregnancy. This latter group was considered the normotensive controls. The rate of preeclampsia and the risk of cardiovascular disease, after onset of preeclampsia, were determined.

Results

Of the 218 women who completed the study, the frequency of hypertensive disorder of pregnancy was 16.5% (36 of 218) and of preeclampsia was 13.8% (30 of 218). Women with preeclampsia had a higher body mass index (BMI), mean of 25.3 ± 4.8 compared to 23.5 ± 3.7 for the normotensive controls, p = 0.02. The risk of preeclampsia increased with BMI [Odds ratio (OR) 1.12, 95% Confidence Interval (CI = 1.02;1.24, p-value = 0.023)]. Women with preeclampsia developed chronic hypertension more often than normotensive controls (p = 0.043) and their systolic and ambulatory blood pressure monitoring was elevated (p = 0.034). Women with preeclampsia had higher BMI even 5 years post-pregnancy (p = 0.008).

Conclusions

Women who are overweight or older have an increased risk of preeclampsia. Previous history of preeclampsia increases the risk of early onset of chronic hypertension. Therefore, effective preventive measures are needed, particularly women at lower social economic stratum who have less access to proper medical care and adequate nutrition.

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

OBJECTIVE

To analyze the clinical variants, outcomes, and prognosis of Guillain-Barré syndrome (GBS) in a Brazilian population.

MATERIALS AND METHODS

Clinical and laboratory data of 149 cases of GBS diagnosed from 1994 to 2007 were analyzed.

RESULTS

Acute inflammatory demyelinating polyneuropathy (AIDP) was the most frequent variant (81.8%) of GBS, followed by acute motor axonal neuropathy (AMAN) (14.7%) and acute motor and sensory axonal neuropathy (AMSAN) (3.3%). The incidence of GBS was 0.3/100,000 for the state of Rio Grande do Norte and cases occurred at a younger age. GBS was preceded by infections, with the axonal variant associated with episodes of diarrheas (P = 0.025). Proximal weakness was more frequent in AIDP, and distal weakness predominant in the axonal variant. Compared to 42.4% of cases with AIDP (P < 0.0001), 84.6% of cases with the axonal variant had nadir in <10 days. Individuals with the axonal variant took longer to recover deambulation (P < 0.0001). The mortality of GBS was 5.3%.

CONCLUSION

A predominance of the AIDP variant was seen, and the incidence of the disease decreased with age. As expected, the distribution of weakness correlated with the clinical variants, and individuals with the axonal variant had a poorer prognosis.

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 Hansen's 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. Hansen's 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 Hansen's disease, pointing to areas where intervention efforts can be targeted to control disease.

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

The resurgence of visceral leishmaniasis in Brazil increases the need for studies to elucidate the spatial and temporal dynamics of Lutzomyia longipalpis (Lutz and 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.

Anti-ganglioside antibodies and clinical outcome of patients with Guillain-Barré Syndrome in northeast Brazil

OBJECTIVES

The goal of this study was to investigate the frequency of GM1 antibodies and to assess whether exposure to Campylobacter jejuni was associated with a distinct clinical variant of Guillain-Barré Syndrome (GBS) or disease outcome in Rio Grande do Norte, Brazil.

MATERIAL AND METHODS

Forty-one patients with a presumed diagnosis of GBS were enrolled and prospectively studied between June 1994 and November 1999.

RESULTS

Anti-GM1 was present in 51.2% (n = 21) of patients. The presence of anti-GM1 was significantly associated with acute axonal motor neuropathy when compared to acute inflammatory demyelinating polyneuropathy (P = 0.01). Patients with anti-GM1 antibodies presented distal muscle involvement and fewer sensory deficits. Age, time to nadir and ventilatory assistance were not associated with anti-GM1 antibodies. Eight out of 21 patients (32%) presented with anti-C. jejuni antibodies. Clinical features were similar for patients with GBS with positive and negative C. jejuni antibodies. Anti-GM1 antibodies were associated with C. jejuni infection (P = 0.0005). Presence of anti-GM1 and C. jejuni antibodies did not indicate a worse prognosis.

CONCLUSION

Patients with GBS and anti-GM1 antibodies had more distal muscle weakness, fewer sensory deficits, more axonal degeneration and C. jejuni infection, but these findings were not associated with a worse prognosis.