RESUMO

The aim of this study was to determine the occurrence of zoonotic enteroparasites in the feces of dogs from public shelters, squares, parks, and public roads in the city of Guarapuava, Paraná, Brazil, and to evaluate the perception of dog guardians regarding zoonoses and their risk to public health. Fecal samples were collected, coproparasitological examinations were performed to detect zoonotic enteroparasites, and polymerase chain reaction (PCR) was used to identify Giardia spp. and Cryptosporidium spp. Questionnaires were given to guardians who walked their dogs in parks, squares, and public roads, as to assess their perception of zoonoses. A total of 333 samples were collected, of these 75, 123, and 135 of them were from public shelters, squares and parks, and public roads, respectively. One or more parasites were identified in 166 (50 %) samples, of which 58/75 (77 %) were from public shelters, 50/123 (41 %) from squares and parks, and 58/135 (43 %) from public roads. The parasites detected included Ancylostoma spp., Giardia spp., Trichuris spp., Toxocara spp., and Cystoisospora spp., with Ancylostoma spp. having the highest occurrence. PCR was performed on 161 samples for convenience due to financial limitations, because only a portion of the study was funded by the municipal government, of which 15.6 % were positive for Giardia spp., and all were negative for Cryptosporidium spp. In total, 246 guardians were interviewed, of which 36 % said they did not collect their animals' feces during walks, 20 % did not use anti-helminthics on their dogs, and 23 % did not know which diseases could be transmitted by feces. Therefore, we conclude that there is a high infection rate of parasites with zoonotic potential in public places, showing the need to raise awareness among guardians about the diseases transmitted by dog feces, correct vermifugation and the importance of collecting feces in public places.

Assuntos

Criptosporidiose , Cryptosporidium , Doenças do Cão , Parasitos , Animais , Cães , Saúde Pública , Brasil/epidemiologia , Zoonoses/epidemiologia , Fezes/parasitologia , Percepção , Doenças do Cão/epidemiologia , Doenças do Cão/parasitologia , Prevalência

RESUMO

A remarkable characteristic of infectious diseases classified as Neglected Tropical Diseases (NTDs) is the fact that they are mostly transmitted in tropical and subtropical regions with poor conditions of sanitation and low access to healthcare, which makes transmission areas more likely to overlap. Two of the most important NTDs, schistosomiasis and leishmaniasis, despite being caused by very different etiological agents, have their pathogenesis heavily associated with immune-mediated mechanisms, and Schistosoma spp. and Leishmania spp. have been shown to simultaneously infect humans. Still, the consequences of Schistosoma-Leishmania coinfections remain underexplored. As the inflammatory processes elicited by each one of these parasites can influence the other, several changes have been observed due to this coinfection in naturally infected humans, experimental models, and in vitro cell assays, including modifications in susceptibility to infection, pathogenesis, prognostic, and response to treatment. Herein, we review the current knowledge in Schistosoma-Leishmania coinfections in both human populations and experimental models, with special regard to how schistosomiasis affects tegumentary leishmaniasis, discuss future perspectives, and suggest a few steps to further improve our understanding in this model of parasite-host-parasite interaction.

RESUMO

Canine soil-transmitted helminths (STHs) cause important zoonoses in the tropics, with varying degrees of intensity of infection in humans and dogs. This study aimed to investigate the prevalence and associated risk factors for STHs in community dogs residing in Grenada, West Indies. In May 2021, 232 canine fecal samples were examined for zoonotic helminths by microscopy (following flotation), and genomic DNA from a subset of 211 of these samples were subjected to multiplex qPCR for the detection and specific identification of hookworms, Toxocara spp. and Strongyloides. Microscopic examination revealed that 46.5% (108/232, 95% CI 40­52.9), 9% (21/232, 95% CI 5.35­12.7) and 5.2% (12/232, 95% CI 2.3­8) of the samples contained eggs of Ancylostoma spp., Toxocara spp. and Trichuris vulpis, respectively. Multiplex qPCR revealed that, 42.2% (89/211, 95% CI 35.5­48.8) were positive for at least 1 zoonotic parasite. Of these, 40.8% (86/211, 95% CI 34.1­47.3) of samples tested positive for Ancylostoma spp., 36% (76/211, 95% CI 29.5­42.9) were positive for A. caninum, 13.3% (28/211, 95% CI 9­18.6) for A. ceylanicum, 5.7% for T. canis (12/211, 95% CI 2.97­8.81) and 1% (2/211, 95% CI 0­2.26) for Strongyloides spp. (identified as S. stercoralis and S. papillosus by conventional PCR-based Sanger sequencing). Using a multiple logistic regression model, a low body score and free-roaming behaviour were significant predictors of test-positivity for these parasitic nematodes in dogs (P < 0.05). Further studies of zoonotic STHs in humans should help elucidate the public health relevance of these parasites in Grenada.

Assuntos

Doenças do Cão , Helmintos , Animais , Cães , Humanos , Ancylostoma , Doenças do Cão/epidemiologia , Doenças do Cão/parasitologia , Fezes/parasitologia , Granada/epidemiologia , Helmintos/classificação , Helmintos/genética , Prevalência , Fatores de Risco , Toxocara , Zoonoses/epidemiologia

RESUMO

Intestinal parasites are a constant public health problem in the Amazon region, with a high prevalence of cases related to poor sanitary conditions. We investigated the sociodemographic and seasonal factors associated with human intestinal parasite infections in an area of the Western Amazon, Brazil, from September 2017 to August 2019. Data were collected using a database available at the Diagnostic Support Centre (Centro de Apoio ao Diagnóstico, CAD) of the Municipality of Rio Branco, on positive diagnoses for intestinal parasites. Among the 53,200 samples analysed, 18.3% (n = 9712) were positive. Of these, 96.4% (n = 9363) and 3.6% (n = 349) were protozoan and helminthic infections, respectively. Males showed higher odds ratio (OR) for Enterobius vermicularis infection (OR: 2.3) and giardiasis (OR: 1.9) and lower OR for Endolimax nana (OR: 0.9) and Entamoeba coli (OR: 0.9) infections. Individuals aged ≥ 15 presented higher OR for Strongyloides stercoralis (OR: 3.4), hookworms (OR: 2.3), and almost all protozoan infections than younger individuals. In the dry season, the OR for hookworms (OR: 1.5), Iodamoeba butschlii (OR: 1.4), and Endolimax nana (OR: 1.3) infections was higher than that in the rainy season, including a high chance of polyparasitism (OR: 1.6). We concluded that there was a significant difference between the different types of intestinal parasites, particularly protozoa, with high OR in the dry season and for certain groups.

Assuntos

Giardíase , Helmintíase , Enteropatias Parasitárias , Infecções por Protozoários , Masculino , Humanos , Estações do Ano , Fezes/parasitologia , Enteropatias Parasitárias/epidemiologia , Enteropatias Parasitárias/parasitologia , Helmintíase/epidemiologia , Helmintíase/parasitologia , Infecções por Protozoários/epidemiologia , Infecções por Protozoários/parasitologia , Prevalência

RESUMO

Intestinal parasitism is the main cause of disease all over the world and described as a significant community health problem. The current study intended to find out the occurrence and identification of hazard factors linked with IPIs among 4-12 years aged shool-age children residing in Lower Dir district, Pakistan during 2019 - 2020. A cross-sectional school-based study was conducted using a pre-arranged pre-tested survey. Anthropometric data and stool collection were done to obtain the findings. The direct wet mount preparation in saline/iodine/methods was used for stool examination. Data were investigated using the GraphPad Prism 5. A total of 400 children studied (mean age of 8.6±3.6 years) the total incidence rate for the intestinal parasitic disease was established to be 71.75%. Of the 400 children studied, the overall prevalence rate for intestinal parasitic infections was found to 71.75% Ascaris lumbricoides (33.1%), Trichuris trichiura (1.04%), E. vermicularis (1.39%), Hookworm (19.86%) were identified in children living in the study area. We concluded that there is a mass scale campaigns were required to generate alertness about health and sanitation in children and the need for the development of effective poverty control programs because deworming (killing of worm with drugs) alone is not adequate to control parasitic infections.

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O parasitismo intestinal é a principal causa de doença em todo o mundo e descrito como um importante problema de saúde comunitária. O presente estudo buscou descobrir a ocorrência e identificação de fatores de risco relacionados a infecções parasitárias intestinais (IPIs) entre crianças em idade escolar de 4 a 12 anos residentes no distrito de Lower Dir, Paquistão durante 2019-2020. Um estudo transversal baseado em escola foi realizado usando uma pesquisa preestabelecida e pré-testada. Dados antropométricos e coleta de fezes foram feitos para obtenção dos achados. A preparação de montagem úmida direta em solução salina/iodo/métodos foi usada para exame de fezes. Os dados foram investigados usando o GraphPad Prism 5. Em um total de 400 crianças estudadas (idade média de 8,6±3,6 anos), a taxa de incidência total da parasitose intestinal foi estabelecida em 71,75%. Das 400 crianças estudadas, a taxa de prevalência global de infecções parasitárias intestinais foi de 71,75%. Ascaris lumbricoides (33,1%), Trichuris trichiura (1,04%), E. vermicularis (1,39%), Ancilostomíase (19,86%) foram identificados em crianças morando na área de estudo. Concluímos que há necessidade de campanhas em massa para gerar alerta sobre saúde e saneamento nas crianças, e a necessidade do desenvolvimento de programas efetivos de controle da pobreza, pois a desparasitação por si só não é adequada para controlar as infecções parasitárias.

Assuntos

Doenças Parasitárias , Área Urbana , Nematoides/parasitologia , Paquistão

RESUMO

The eradication of the vector Rhodnius prolixus from Central America was heralded as a victory for controlling transmission of Trypanosoma cruzi, the parasite that causes Chagas disease. While public health officials believed this milestone achievement would effectively eliminate Chagas disease, case reports of acute vector transmission began amassing within a few years. This investigation employed a cross-sectional serosurvey of children either presenting with fever for clinical care or children living in homes with known triatomine presence in the state of Sonsonate, El Salvador. Over the 2018 calendar year, a 2.3% Chagas disease seroprevalence among children with hotspot clustering in Nahuizalco was identified. Positive serology was significantly associated with dogs in the home, older participant age, and a higher number of children in the home by multivariate regression. Concomitant intestinal parasitic infection was noted in a subset of studied children; 60% having at least one intestinal parasite and 15% having two or more concomitant infections. Concomitant parasitic infection was statistically associated with an overall higher parasitic load detected in stool by qPCR. Lastly, a four-fold higher burden of stunting was identified in the cohort compared to the national average, with four-fifths of mothers reporting severe food insecurity. This study highlights that polyparasitism is common, and a systems-based approach is warranted when treating Chagas disease seropositive children.

RESUMO

Cystic echinococcosis is a worldwide zoonosis caused by the cestode Echinococcus granulosus. Two types of hydatid cysts occur in intermediate hosts: fertile cysts that generate protoscoleces from the germinal layer of the cyst, and infertile cysts that do not produce protoscoleces and are unable to continue the life cycle of the parasite. The adventitial layer, a host-derived fibrous capsule surrounding the hydatid cyst, is suggested to play an important role in local immune regulation during infection and in fertility of the cysts. Fasciola hepatica, another important parasite of cattle, induces a characteristic Th2-like immune response that could modulate the immune response against E. granulosus. Natural co-infection of both parasites is common in cattle, but no reports describe the local immune response against E. granulosus with F. hepatica infection in the same host. This study analyzed the number and distribution of T and B cells in the adventitial layer of liver and lung cysts and the relationship with cyst fertility and F. hepatica co-infection. T lymphocytes were the predominant cell type in the adventitial layer of infertile hydatid cysts and were more numerous in infertile hydatid cysts. B lymphocyte numbers were not associated with hydatid cyst fertility. Mast cells were infrequent in the adventitial layer. The number of T and B cells was not associated with F. hepatica co-infection. The present study contributes to the understanding of local immune responses in bovine cystic echinococcosis.

Assuntos

Doenças dos Bovinos/parasitologia , Cistos/veterinária , Equinococose/veterinária , Echinococcus granulosus/imunologia , Fasciola hepatica/imunologia , Fasciolíase/veterinária , Imunidade , Animais , Bovinos , Doenças dos Bovinos/patologia , Coinfecção/veterinária , Cistos/parasitologia , Cistos/patologia , Equinococose/parasitologia , Equinococose/patologia , Fasciolíase/parasitologia , Fasciolíase/patologia , Fertilidade , Fígado/parasitologia , Fígado/patologia , Pulmão/parasitologia , Pulmão/patologia , Subpopulações de Linfócitos

RESUMO

Dogs play an important role as reservoirs and hosts of multiple pathogens shared with humans and wildlife, which contribute significantly to the global burden of disease. Here, we assessed the occurrence of a broad range of zoonotic and non-zoonotic parasites in dogs from a rural area in the humid Chaco; determined the occurrence of polyparasitism; and explored its association with selected risk factors. In total, 212 dogs were examined serologically to determine Trypanosoma cruzi infection and 152 of them also were examined for Ehrlichia canis, Borrelia bugderfori, Anaplasma phagocitophylum, Dirofilaria immitis and Toxoplasma gondii. Fecal samples from 85 dogs were examined for intestinal parasites. Seventeen parasite species were seen, 77% of which are zoonotic. The most prevalent parasites were Ancylostoma caninum (68.2%), T. gondii (55.3%, first report for dogs in Argentina), Giardia sp. (25.9%), Cryptosporidium sp. (20.0%), T. cruzi (16.5%), trematodes (15.3%) and Toxocara canis (14.1%). Polyparasitism was found in 96% of the dogs, with up to six parasite species in a single dog, and was significantly associated with age of dog but not with host body condition or sex. The most frequent pair of parasites found together were T. gondii-A. caninum (46%), A. caninum-T. cruzi (34%) and T. gondii-T. cruzi (27%). The prevalence of anemia and leukocytosis was significantly higher in dogs showing the worst body condition. Our findings likely reflect structural poverty, poor sanitation and lack of a safe water supply. Importantly, many of the prevalent parasites seen are threats to human health. 243 words.

Assuntos

Doenças do Cão/parasitologia , Doenças Parasitárias em Animais/parasitologia , Zoonoses/parasitologia , Animais , Argentina/epidemiologia , Doenças do Cão/epidemiologia , Doenças do Cão/transmissão , Cães , Feminino , Enteropatias Parasitárias/epidemiologia , Enteropatias Parasitárias/parasitologia , Enteropatias Parasitárias/transmissão , Enteropatias Parasitárias/veterinária , Masculino , Doenças Parasitárias em Animais/epidemiologia , Doenças Parasitárias em Animais/transmissão , Prevalência , Fatores de Risco , População Rural , Toxoplasmose Animal/epidemiologia , Toxoplasmose Animal/parasitologia , Toxoplasmose Animal/transmissão , Doenças Transmitidas por Vetores/epidemiologia , Doenças Transmitidas por Vetores/parasitologia , Doenças Transmitidas por Vetores/transmissão , Doenças Transmitidas por Vetores/veterinária , Zoonoses/epidemiologia , Zoonoses/transmissão

RESUMO

BACKGROUND: Natural parasite infection occurs in wild and domestics animals with more than one parasite species at the same time, generating an infection called polyparasitism. Cystic echinococcosis reports are usually based only on infection with Echinoccocus granulosus leaving aside other internal parasitoses that could modulate both the immune response and pathogenesis of the natural infection. Fasciola hepatica is another cosmopolitan parasite in ruminants with a similar distribution to E. granulosus in different parts of the world, but no information of the effect of co-infection with E. granulosus has been described. The aims of this report were to establish E. granulosus prevalence and explore the association of F. hepatica co-infection and natural E. granulosus infections in cattle. RESULTS: From 1725 animals, the prevalence of E. granulosus and F. hepatica was 21.16 and 51.3%, respectively. Considering both infections, older cattle (> 4 years) presented higher prevalence compared to younger animals. In E. granulosus-infected cattle, 5.21% had fertile cysts, 71.78% infertile cysts, and in 23.01% cysts were smaller than 1 cm in diameter. Considering cyst location, 39.72% had lungs cysts, 24.72% had liver cysts and 36.94% had cysts in both organs. Cyst location significantly differed between age groups: 44.68% of younger animals had cysts only in the lungs, while older animals presented hydatid cyst in the lungs and liver simultaneously (44.15%). With E. granulosus infection alone, 30.26% of cysts were found in the lungs, 31.79% in the liver and 37.95% in both organs. Regarding the co-infection of E. granulosus with F. hepatica, the proportion was significantly different (P < 0.05) with most animals having cysts only in the lungs (49.41%) and a lower level of liver infection (15.88%). Analyzing organ cyst distribution and F. hepatica absence/presence ratio within each cyst type, small cysts showed the highest difference in ratio. CONCLUSIONS: To the best of our knowledge, this is the first report indicating that F. hepatica co-infection in cattle could be affecting the instate of hydatid cysts in the liver, displacing toward lung localization, suggesting an antagonistic relationship.

Assuntos

Doenças dos Bovinos/parasitologia , Coinfecção/parasitologia , Equinococose/veterinária , Echinococcus granulosus/isolamento & purificação , Fasciola hepatica/isolamento & purificação , Fasciolíase/veterinária , Fatores Etários , Animais , Bovinos/parasitologia , Doenças dos Bovinos/epidemiologia , Coinfecção/epidemiologia , Cistos/epidemiologia , Cistos/parasitologia , Equinococose/epidemiologia , Equinococose/parasitologia , Echinococcus granulosus/fisiologia , Fasciola hepatica/fisiologia , Fasciolíase/epidemiologia , Fígado/parasitologia , Hepatopatias/epidemiologia , Hepatopatias/parasitologia , Pulmão/parasitologia , Prevalência

RESUMO

Interactions among different species of parasites co-infecting the same host could be synergistic or antagonistic. These interactions may modify both the frequency of infected hosts and their infectiousness, and therefore impact on transmission dynamics. This study determined the infectiousness of Trypanosoma cruzi-seropositive dogs (using xenodiagnosis) and their parasite load (quantified by qPCR), and tested the association between both variables and the presence of concomitant endoparasites. A cross-sectional serosurvey conducted in eight rural villages from Pampa del Indio and neighboring municipalities (northeastern Argentina) detected 32 T. cruzi-seropositive dogs out of 217 individuals examined for infection. Both the infectiousness to the vector Triatoma infestans and parasite load of T. cruzi-seropositive dogs examined were heterogeneous. A statistically significant, nine-fold higher mean infectiousness was registered in T. cruzi-seropositive dogs co-infected with Ancylostoma caninum and a trematode than in T. cruzi-seropositive dogs without these infections. The median parasite load of T. cruzi was also significantly higher in dogs co-infected with these helminths. An opposite trend was observed in T. cruzi-seropositive dogs that were serologically positive to Toxoplasma gondii or Neospora caninum relative to dogs seronegative for these parasites. Using multiple logistic regression analysis with random effects, we found a positive and significant association between the infectiousness of T. cruzi-seropositive dogs and co-infections with A. caninum and a trematode. Our results suggest that co-infections may be a modifier of host infectiousness in dogs naturally infected with T. cruzi.

Assuntos

Doença de Chagas/veterinária , Coinfecção/veterinária , Doenças do Cão/parasitologia , Trypanosoma cruzi/isolamento & purificação , Animais , Doença de Chagas/complicações , Doença de Chagas/parasitologia , Cães , Helmintíase Animal/complicações , Helmintíase Animal/parasitologia , Helmintíase Animal/patologia

RESUMO

Se realizó un estudio descriptivo y transversal de 320 pacientes mayores de 5 años de edad, cuyos exámenes de heces fecales dieron positivos, atendidos en el Centro de Diagnóstico Integral "Cuyuní" de la parroquia La Sabanita en Ciudad Bolívar (Estado Bolívar de Venezuela), desde julio del 2011 hasta marzo del 2012, a fin de caracterizarles según algunas variables de interés: tipos de parásitos, particularidades del abastecimiento y tratamiento del agua de consumo, lugar de deposición, hábitos higiénico-sanitarios y síntomas más frecuentes. Del total de la serie, 58,4 % presentaba poliparasitismo, 73,7 % se abastecía de agua mediante pipas o tanques y 45,3 % no trataba el agua de consumo, mientras que 66,3 % lo hacía por el método de filtración; asimismo, predominaron la defecación en letrinas (53,1 %), el hábito de andar descalzos (24,7 %), el dolor abdominal entre los síntomas referidos (39,4 %) y la Entamoeba histolytica como parásito más hallado (35,3 %).

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A descriptive and cross-sectional study was carried out in 320 patients over 5 years of age whose stool tests were positive, treated in "Cuyuní" Comprehensive Diagnosis Center from La Sabanita parish in Bolívar city (Bolívar State of Venezuela), from July 2011 to March 2012, in order to characterize them according to some variables of interest: types of parasites, particularities of supply and treatment of drinking water, stools place, health habits and most frequent symptoms. Of the total of the series, 58.4% had polyparasitism, 73.7% were supplied with water by means of tankers or water tanks and 45.3% did not treat drinking water, while 66.3% did so by the filtration method; also, passage of stools in latrines (53.1%), the habit of walking barefoot (24.7%), abdominal pain between the symptoms reported (39.4%) and Entamoeba histolytica as the most found parasite (35.3%) prevailed.

Assuntos

Parasitos , Doenças Parasitárias , Entamoeba histolytica , Água Potável , Água , Aparelho Sanitário , Criança , Purificação da Água , Disenteria Amebiana

RESUMO

Disturbing data reveal the prevalence of intestinal parasites and their relationship with socio-environmental factors among Mbyá-Guarani Indians. The prevalence was determined by spontaneous sedimentation in water, centrifugation-floatation, and Kato-Katz. A socioeconomic questionnaire was submitted to each family. The overall prevalence of intestinal parasites was 88.7%, and 45.5% were polyparasitized. There was 90.5% prevalence of enteric parasites in children (1-12- year-old), and 85% among 13-65-year-old individuals, indicating that both age groups are extensively parasitized. The parasite load was low to moderate for geohelminths and 75% of the families did not have latrine, thus the practice of defecation occurred outdoors. These findings suggest that the multiple intestinal parasitism in the Mbyá-Guarani community is high to the point of being the rule, and that it relates essentially to the traditional lifestyle and health habits. It is urgently necessary to implement the association of anti-parasitic treatment with sanitation improvement. This should be done simultaneously with health education activities for this population.

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Dados preocupantes demonstram a prevalência de parasitos intestinais e sua relação com fatores socioambientais entre indígenas Mbyá-Guarani. A prevalência foi determinada pelas técnicas de sedimentação espontânea em água, centrífugo-flutuação e Kato-Katz. Para cada família, um questionário socioeconômico foi aplicado. A prevalência geral de parasitos intestinais foi de 88,7% e 45,5% estavam poliparasitados. A prevalência em crianças (1-12 anos) foi 90,5% e em indivíduos entre 13-65 anos foi 85%, indicando que ambas as faixas etárias são amplamente parasitadas. A carga parasitária foi baixa a moderada para geohelmintos e 75% das famílias não possuem banheiro, sendo a prática da defecação feita ao ar livre. Estes achados sugerem que o poliparasitismo intestinal na comunidade Mbyá-Guarani é altíssimo, a ponto de ser a regra, e que se refere essencialmente ao estilo de vida tradicional e hábitos de saúde. Há a necessidade de aplicar urgentemente a associação de tratamento antiparasitário às melhorias sanitárias. Isto deve ser feito simultaneamente com atividades de educação em saúde para esta população.

Assuntos

Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Adulto Jovem , Indígenas Sul-Americanos/estatística & dados numéricos , Enteropatias Parasitárias/epidemiologia , Saneamento/estatística & dados numéricos , Brasil/epidemiologia , Fezes/parasitologia , Enteropatias Parasitárias/diagnóstico , Enteropatias Parasitárias/parasitologia , Contagem de Ovos de Parasitas , Prevalência , Fatores de Risco , Índice de Gravidade de Doença

RESUMO

BACKGROUND: Soil transmitted helminths (STH) remain a global public health concern in spite of occasional dosing campaigns. AIMS: To determine baseline prevalence and intensity of STH infection in east Guatemalan school children, and describe the associated epidemiology of anemia, stunting, and wasting in this population. SETTING AND DESIGN: Ten schools in Izabal province (eastern Guatemala) were identified, and 1,001 school children were selected for this study. Half of the schools were used as clinical testing sites (blood and stool). MATERIALS AND METHODS: Anthropometric measures were collected from all children. Over 300 children were tested for anemia and 229 for helminth infection. Ova and parasite specimens were examined via Direct, Kato Katz, and McMaster techniques. Hemoglobin was measured from venipuncture following the hemacue system. STATISTICAL ANALYSIS: Correlation between infection intensities and growth indicators were examined. Chi Square or t tests were used for bivariate analysis. Multiple logistic regression was performed on significant variables from bivariate techniques. RESULTS: Over two-thirds of school children were positive for infection by any STH. Prevalence of Hookworm was 30%; Ascaris, 52%; and Trichuris, 39%, most as low-intensity infection. Over half of the children were co-infected. In bivariate analysis, anemia was significantly associated with polyparasitism. CONCLUSIONS: For a Guatemalan child who experiences a unit decrease in hemoglobin, one expects to see a 24% increase in the odds of being infected with STH, controlling for age, sex, lake proximity, and growth characteristics. Infection with more than one STH, despite low intensity, led to a significant decrease in hemoglobin.

RESUMO

PURPOSE: To determine the prevalence of gastrointestinal parasites and evaluate the effect of a single dose of treatment with albendazole in a sentinel group from a rural community in southern Mexico. METHODS: Stool samples were collected from 1456 individuals aged ≥1 year during consecutive days, and examined for helminth infection using the modified Stoll dilution method. Additionally, 104 individuals were treated with a single dose of albendazole and evaluated over 21 weeks to assess reinfection. Questionnaires were administered to obtain individual and household-level data pertaining to behavior, demography, and socioeconomic status. Risk factors for reinfection after albendazole administration were determined using multiple logistic regression analyses. RESULTS: The prevalence of Ascaris lumbricoides was 73.9% (95% confidence interval [CI] = 71.56%-76.14%). Albendazole was 100% effective, but eggs began to be detected by 9-12 weeks posttreatment, increasing to 100% after 21 weeks. Logistic regression analysis revealed that all individuals from this study had a probability of reinfection of 1.65× each week after treatment. The prevalence of Trichuris trichiura was 57.2% (95% CI = 54.62%-59.77%) and chemotherapy was 34.7% effective. The prevalence for other minor gastrointestinal parasites ranged from 0.2% to 29.7%. CONCLUSION: This was a comprehensive study on gastrointestinal parasites in a rural community from southern Mexico and, to the best of the authors' knowledge, is the first time that the effect of albendazole has been evaluated for a period of over 21 weeks following its administration. Risk factors associated with parasite transmission were linked to poverty and lack of hygiene, such as, defecating in open places, living customs (drinking piped water and/or from a well), and absence of knowledge about transmission life cycle of the parasites. Studies of this kind should be linked to health education and improvement of access to clean water and adequate sanitation to consolidate morbidity control and enhance sustainability.