Related factors to human toxocariasis in a rural community of Argentina

The objective of this study was to evaluate the relationship between toxocariasis frequency and demographic, environmental, sanitary variables, eosinophylia, and other intestinal parasites in a rural population of Argentina. Serological examination of 100 individuals was carried out by using ELISA technique for the detection of anti-toxocara antibodies. Eosinophiles in peripheral blood, presence of intestinal parasites, and demographic, environmental, and socio-cultural data were evaluated. Eighty-one feces samples of dogs belonging to the studied people were analyzed to detect eggs of Toxocara canis. Thirty of them were from 30 dogs and 51 were pools from dog feces. Samples of dirt from around the homes (n: 47) and from public park (n: 4) were taken. To determine the associations, the c² and Fisher tests were used. The seroprevalence was 23%. Eosinophilia in peripheral blood was detected in 86.95% seropositive individuals and in 37.66% seronegative individuals (p < 0.001, OR = 11.03). Of the 23 people with positive serology, 69.56% had at least one intestinal parasite. All individuals with positive serology had dogs in their homes. Among the dog owners there was a significant association between the presence of anti-toxocara antibodies and home flooding. Eggs of T. canis were detected in the feces of 5/81 dogs and three of these dogs belonged to individuals with positive serology. Eggs of Toxocara spp. were found in 41.17% of the dirt samples, eight of which came from the area surrounding the homes of individuals with positive serology (p = 0.032; OR = 4.36). Taking into account all the variables influencing the frequency of toxocariasis in this population, the implementation of Public Health programs specifically focused on anti-parasitic treatment of dogs is recommended.

The impact of two education methods on knowledge of schistosomiasis transmission and prevention among schoolchildren in a rural community in northern Minas Gerais, Brazil

The objective of this study was to analyse the effect of using two health education approaches on knowledge of transmission and prevention of schistosomiasis of school children living in a rural endemic area in the state of Minas Gerais, Brazil. The 87 children participating in the study were divided into three groups based on gender, age and presence or absence of Schistosoma mansoni infection. In the first group the social representation model and illness experience was used. In the second group, we used the cognitive model based on the transmission of information. The third group, the control group, did not receive any information related to schistosomiasis. Ten meetings were held with all three groups that received a pre-test prior to the beginning of the educational intervention and a post-test after the completion of the program. The results showed that knowledge levels in Group 1 increased significantly during the program in regard to transmission (p = 0.038) and prevention (p = 0.001) of schistosomiasis. Groups 2 and 3 did not show significant increase in knowledge between the two tests. These results indicate that health education models need to consider social representation and illness experience besides scientific knowledge in order to increase knowledge of schistosomiasis transmission and prevention.

Typing of Mycobacterium tuberculosis strains isolated in Community Health Centers of Rio de Janeiro City, Brazil

Fingerprinting of Mycobacterium tuberculosis strains from tuberculosis (TB) patients attended in Community Health Centers (CHCs) of Rio de Janeiro was performed to verify possible risk factors for TB transmission. A prospective community-based study was performed during the period of July 1996 to December 1996 by collecting sputum samples of 489 patients in 11 different CHCs in four different planning areas (APs) of the city. Bacteriological, clinical, and epidemiological information was collected and M. tuberculosis genotypes defined after restriction fragment length polymorphism (IS6110-RFLP) and double repetitive element (DRE) fingerprinting of RFLP-clustered cases. Risk factors for TB transmission were looked for using three levels of cluster stringency. Among 349 (71%) positive cultures obtained, IS6110-RFLP typing could be performed on strains from 153 different patients. When using identity of RFLP patterns as cluster definition, 49 (32%) of the strains belonged to a cluster and none of the clinical or epidemiologic characteristics was associated with higher clustering levels. However, higher clustering level was observed in the AP including the central region of the city when compared to others. This strongly suggests that more recent transmission occurs in that area and this may be related with higher incidence of TB and HIV in this region.

A thirty years follow-up study on Schistosomiasis mansoni in a community of Minas Gerais, Brazil

During thirty years - 1973-2003 - a group of individuals infected by Schistosoma mansoni in Capitão Andrade, Rio Doce Valley, Minas Gerais, Brazil, was evaluated by the same authors, being one of the longest follow-up studies on schistosomiasisis mansoni in an endemic area. The diagnosis of S. mansoni was based on parasitological stool tests. In the clinical classification, three groups were considered: type I - schistosomiasis-infection, type II - hepatointestinal form, and type III- hepatosplenic form. The prevalence of infection were 60.8% in 1973, 36.2% in 1984, 27.3% in 1994, and 19.4% in 2003, while the index of hepatosplenomegaly were respectively 5.8%, 2.8%, 2.3% and 1.3%. The maintenance of high prevalence and severity of clinical forms are probably related to reinfection.

Hepatitis A virus subgenotypes dissemination during a community outbreak in a surrounding region of Rio de Janeiro

From December 1999 to December 2001, many cases of hepatitis A were notified in the county of Belford Roxo involving individuals aged 0 to 79 years. Serum samples were collected to evaluate the prevalence of anti-hepatitis A virus (HAV) antibodies, to detect HAV-RNA and to correlate with possible risk factors of HAV infection. Serum samples were screened by commercial IgM and total anti-HAV antibody ELISA and HAV-RNA was isolated and subsequently amplified by reverse transcription-polymerase chain reaction (RT-PCR) at VP1/2A region, sequenced and analyzed. Total anti-HAV prevalence was 87.9% (203/231) and IgM anti-HAV prevalence was 38.7% (89/231). Multivariate analysis showed that individuals under 20 years old are risks groups to acquire the infection suggesting that hygienic habits of young subjects are the principal factor of transmission and so they could be the target for vaccine programs. HAV-RNA was amplified from 29 (32.5%) IgM anti-HAV positive patients and 26 samples were sequenced and classified into subgenotypes IB (8 isolates) and IA (18 isolates). Isolates classified into subgenotype IB were identical representing one distinct strain. We could observe both subgenotypes circulating during the study which suggests different sources of infection. Prophylactic measures as vaccination strategies added to improvements in hygienic and sanitary conditions would be highly effective to reduction of infection.

Relationship among epidemiological parameters of six childhood infections in a non-immunized Brazilian community

Epidemiological parameters, such as age-dependent force of infection and average age at infection () were estimated for rubella, varicella, rotavirus A, respiratory syncytial virus, hepatitis A and parvovirus B19 infections for a non-immunized Brazilian community, using the same sera samples. The for the aforementioned diseases were 8.45 years (yr) [95% CI: (7.23, 9.48) yr], 3.90 yr [95% CI: (3.51, 4.28) yr], 1.03 yr [95% CI: (0.96, 1.09) yr], 1.58 yr [95% CI: (1.39, 1.79) yr], 7.17 yr [95% CI: (6.48, 7.80) yr] and 7.43 yr [95% CI: (5.68, 9.59) yr], respectively. The differences between average ages could be explained by factors such as differences in the effectiveness of the protection conferred to newborns by maternally derived antibodies, competition between virus species and age-dependent host susceptibility. Our seroprevalence data may illustrate a case of the above-mentioned mechanisms working together within the same population.

Spatial distribution of Schistosoma mansoni infection before and after chemotherapy with two praziquantel doses in a community of Pernambuco, Brazil

Praziquantel chemotherapy has been the focus of the Schistosomiasis Control Program in Brazil for the past two decades. Nevertheless, information on the impact of selective chemotherapy against Schistosoma mansoni infection under the conditions confronted by the health teams in endemic municipalities remains scarce. This paper compares the spatial pattern of infection before and after treatment with either a 40 mg/kg or 60 mg/kg dose of praziquantel by determining the intensity of spatial cluster among patients at 180 and 360 days after treatment. The spatial-temporal distribution of egg-positive patients was analysed in a Geographic Information System using the kernel smoothing technique. While all patients became egg-negative after 21 days, 17.9% and 30.9% reverted to an egg-positive condition after 180 and 360 days, respectively. Both the prevalence and intensity of infection after treatment were significantly lower in the 60 mg/kg than in the 40 mg/kg treatment group. The higher intensity of the kernel in the 40 mg/kg group compared to the 60 mg/kg group, at both 180 and 360 days, reflects the higher number of reverted cases in the lower dose group. Auxiliary, preventive measures to control transmission should be integrated with chemotherapy to achieve a more enduring impact.

The prevalence of schistosomiasis in school-aged children as an appropriate indicator of its prevalence in the community

School-aged children (6-15 years) from the endemic area of Pernambuco were evaluated both as a target group for and an indicator of schistosomiasis control in the community. Parasitological data were drawn from baseline stool surveys of whole populations that were obtained to diagnose Schistosoma mansoni infection. Nineteen representative localities were selected for assessing the prevalence of schistosomiasis among individuals in the following age groups: 0-5, 6-15, 16-25, 26-40 and 41-80 years. For each locality, the prevalence in each age group was compared to that of the overall population using contingency table analysis. To select a reference group, the operational difficulties of conducting residential surveys were considered. School-aged children may be considered to be the group of choice as the reference group for the overall population for the following reasons: (i) the prevalence of schistosomiasis in this age group had the highest correlation with the prevalence in the overall population (r = 0.967), (ii) this age group is particularly vulnerable to infection and plays an important role in parasite transmission and (iii) school-aged children are the main target of the World Health Organization in terms of helminth control. The Schistosomiasis Control Program should consider school-aged children both as a reference group for assessing the need for intervention at the community level and as a target group for integrated health care actions of the Unified Health System that are focused on high-risk groups.

Bat flies on phyllostomid hosts in the Cerrado region: component community, prevalence and intensity of parasitism

Streblidae flies are specialised parasites of bat hosts, mainly phyllostomids. There is a high richness of streblids in the savannah-like Cerrado region; however, there is little quantitative data available in parasitological indices. Here, we describe the component community, prevalence and intensity of a streblid infestation on a phyllostomid bat assemblage in Serra da Bodoquena, a Cerrado region in Southwest Brazil. We conducted surveys by capturing and inspecting bat hosts during the seven-month period between October 2004-December 2005. All the ectoparasites found on the bats were collected in the field and then counted and identified in the laboratory. We captured 327 bats belonging to 13 species, of which eight species were parasitized by 17 species of streblids. Carollia perspicillata and Glossophaga soricina were infested with seven streblid species, whereas the other bat species were infested with four or fewer streblid species. Megistopoda proxima and Aspidoptera falcata flies were found on Sturnira lilium, and Trichobius joblingi was the most prevalent fly on C. perspicillata. Megistopoda aranea and Aspidoptera phyllostomatis were highly prevalent and had a high intensity of infestation on Artibeus planirostris. Overall comparisons of the available data suggest that the component communities of streblids vary more between the Cerrado and Atlantic Forest phytogeographical regions than between localities within the same phytogeographical region.

Acute diarrhoea in a community cohort of children who received an oral rotavirus vaccine in Northeast Brazil

Rotavirus is an important cause of childhood diarrhoea. A monovalent rotavirus vaccine (Rotarix®) was introduced into the Immunization Program of Brazil in 2006. In this study, we describe the incidence and burden of disease of rotavirus diarrhoea in two cohorts of children (vaccinated and unvaccinated). We followed two groups of 250 children under one year old, who were enrolled in December 2006 from a low-income residential area in Northeast Brazil. The children were monitored every two weeks for two years. Stool samples from children with diarrhoea were examined for the presence of rotavirus. Rotaviruses were genotyped using real time-polymerase chain reaction. The mean numbers of all-cause diarrhoea episodes/child (adjusted for age) in the first year were 0.87 and 0.84, in vaccinated and unvaccinated children, respectively. During the second year, the number of episodes/child decreased to 0.52 and 0.42. Only 16 (4.9%) of 330 stool samples were rotavirus-positive (10 vaccinated and 6 unvaccinated children) and only P[4]G2 rotaviruses were identified. All-cause diarrhoea episodes were more severe in unvaccinated children in the first year of age (p < 0.05), while vaccinated children had more severe episodes 18 months after vaccination. Rotavirus diarrhoea incidence was very low in both groups.

Time-based distribution of Staphylococcus saprophyticus pulsed field gel-electrophoresis clusters in community-acquired urinary tract infections

The epidemiology of urinary tract infections (UTI) by Staphylococcus saprophyticus has not been fully characterised and strain typing methods have not been validated for this agent. To evaluate whether epidemiological relationships exist between clusters of pulsed field gel-electrophoresis (PFGE) genotypes of S. saprophyticus from community-acquired UTI, a cross-sectional surveillance study was conducted in the city of Rio de Janeiro, Brazil. In total, 32 (16%) female patients attending two walk-in clinics were culture-positive for S. saprophyticus. Five PFGE clusters were defined and evaluated against epidemiological data. The PFGE clusters were grouped in time, suggesting the existence of community point sources of S. saprophyticus. From these point sources, S. saprophyticus strains may spread among individuals.

Impact of a community-based bug-hunting campaign on Chagas disease control: a case study in the department of Jalapa, Guatemala

Chagas disease control requires an innovative approach to strengthen community participation in vector surveillance. This paper presents a case study of a community-based bug-hunting campaign in Guatemala. The campaign was implemented in 2007 in the following three stages: (i) a four week preparation stage to promote bug-hunting, (ii) a one week bug-hunting stage to capture and collect bugs and (iii) a 10 week follow-up stage to analyse the bugs and spray insecticide. A total of 2,845 bugs were reported, of which 7% were Triatominae vectors, such as Rhodnius prolixus and Triatoma dimidiata. The bug-hunting campaign detected a five-six-fold higher amount of vectors in one week than traditional community-based surveillance detects in one year. The bug-hunting campaign effectively detected vectors during a short period, provided information to update the vector infestation map and increased community and political awareness regarding Chagas disease. This approach could be recommended as an effective and feasible strategy to strengthen vector surveillance on a larger scale.

A comparative cross-sectional study on the prevalence and morbidity of schistosomiasis in a community in northeastern Brazil (1979-2010)

A cross-sectional study on the prevalence and morbidity of schistosomiasis was conducted in the main settlement of the municipality of Alhandra, in the southern coastal region of the state of Paraíba, in 2010. The results of this study were compared with the results of a previous study conducted in the same area in 1979. The systematic sampling per family conglomerate included approximately 10% of the resident population in the urban area of Alhandra. Faecal examinations were performed using the Kato-Katz method. The clinical forms of the disease were classified in accordance with FS Barbosa as Type I - intestinal form, Type II - hepatointestinal form and Type III - hepatosplenic form. The prevalence of the infection in 2010 was 10.05%, whereas in 1979 it was 46.6% among untreated patients. The percentages of the three clinical forms in 2010 were as follows: 95.3% Type I, 4.6% Type II and 0% Type III; in 1979, the percentages were 94.4%, 3% and 2.6% for Types I, II and III, respectively. In 1979, 6.07% of the Biomphalaria glabrata specimens (the intermediate host in this area) excreted cercariae, where in 2010 only 1.27% of the specimens caught excreted the parasite.

Risk factors associated with Trypanosoma cruziexposure in domestic dogs from a rural community in Panama

Chagas disease, caused by Trypanosoma cruzi infection, is a zoonosis of humans, wild and domestic mammals, including dogs. In Panama, the main T. cruzi vector is Rhodnius pallescens, a triatomine bug whose main natural habitat is the royal palm, Attalea butyracea. In this paper, we present results from three T. cruzi serological tests (immunochromatographic dipstick, indirect immunofluorescence and ELISA) performed in 51 dogs from 24 houses in Trinidad de Las Minas, western Panama. We found that nine dogs were seropositive (17.6% prevalence). Dogs were 1.6 times more likely to become T. cruziseropositive with each year of age and 11.6 times if royal palms where present in the peridomiciliary area of the dog’s household or its two nearest neighbours. Mouse-baited-adhesive traps were employed to evaluate 12 peridomestic royal palms. All palms were found infested with R. pallescens with an average of 25.50 triatomines captured per palm. Of 35 adult bugs analysed, 88.6% showed protozoa flagellates in their intestinal contents. In addition, dogs were five times more likely to be infected by the presence of an additional domestic animal species in the dog’s peridomiciliary environment. Our results suggest that interventions focused on royal palms might reduce the exposure to T. cruzi infection.