Risk factors for gastrointestinal parasite infections of dogs living around protected areas of the Atlantic Forest: implications for human and wildlife health / Fatores de risco para infecções parasitárias gastrointestinais em cães do entorno de áreas protegidas da Mata Atlântica: implicações para a saúde humana e da vida selvagem

Abstract Despite the ubiquity of domestic dogs, their role as zoonotic reservoirs and the large number of studies concerning parasites in urban dogs, rural areas in Brazil, especially those at the wildlife-domestic animal-human interface, have received little attention from scientists and public health managers. This paper reports a cross-sectional epidemiological survey of gastrointestinal parasites of rural dogs living in farms around Atlantic Forest fragments. Through standard parasitological methods (flotation and sedimentation), 13 parasite taxa (11 helminths and two protozoans) were found in feces samples from dogs. The most prevalent were the nematode Ancylostoma (47%) followed by Toxocara (18%) and Trichuris (8%). Other less prevalent (<2%) parasites found were Capillaria, Ascaridia, Spirocerca, Taeniidae, Acantocephala, Ascaris, Dipylidium caninum, Toxascaris, and the protozoans Cystoisospora and Eimeria. Mixed infections were found in 36% of samples, mostly by Ancylostoma and Toxocara. Previous deworming had no association with infections, meaning that this preventive measure is being incorrectly performed by owners. Regarding risk factors, dogs younger than one year were more likely to be infected with Toxocara, and purebred dogs with Trichuris. The number of cats in the households was positively associated with Trichuris infection, while male dogs and low body scores were associated with mixed infections. The lack of associations with dog free-ranging behavior and access to forest or villages indicates that infections are mostly acquired around the households. The results highlight the risk of zoonotic and wildlife parasite infections from dogs and the need for monitoring and controlling parasites of domestic animals in human-wildlife interface areas.

Resumo Apesar da ubiquidade dos cães domésticos, de seu papel como reservatório de doenças, e do grande número de estudos sobre parasitas de cães urbanos, as áreas rurais no Brasil, especialmente aquelas na interface entre animais silvestres - animais domésticos - humanos, tem recebido pouca atenção de cientistas e gestores de saúde pública. Este artigo relata um estudo epidemiológico seccional de parasitas gastrointestinais de cães rurais em propriedades no entorno de fragmentos de Mata Atlântica. Através de métodos parasitológicos como flutuação e sedimentação, 13 táxons de parasitas (11 helmintos e dois protozoários) foram encontrados em amostras de fezes dos cães. O mais prevalente foi o nematóide Ancylostoma (47%), seguido por Toxocara (18%) e Trichuris (8%). Outros parasitas menos prevalentes (<2%) encontrados foram Capillaria, Ascaridia, Spirocerca, Taeniidae, Acantocephala, Ascaris, Dipylidium caninum, Toxascaris, e os protozoários Cystoisospora and Eimeria. Infecções mistas foram detectadas em 36% das amostras, a maioria por Ancylostoma e Toxocara. Vermifugações prévias não foram associadas a infecções, indicando que esta medida preventiva está sendo realizada incorretamente pelos proprietários. Com relação aos fatores de risco, cães com menos de um ano tiveram maior probabilidade de infecção por Toxocara, e os cães de raça pura por Trichuris. O número de gatos na propriedade foi associado positivamente com a infecção por Trichuris, enquanto cães machos e baixos escores corporais foram associados a infecções mistas. A ausência de associações com comportamento de vida livre e acesso a florestas ou vilas pelos cães indica que as infecções estão sendo predominantemente adquiridas nas propriedades. Os resultados destacam o risco de infecções parasitárias zoonóticas e para animais silvestres a partir dos cães, e a necessidade de monitorar e controlar os parasitas de animais domésticos em áreas de interface entre humanos e a vida selvagem.

Risk factors for gastrointestinal parasite infections of dogs living around protected areas of the Atlantic Forest: implications for human and wildlife health.

Despite the ubiquity of domestic dogs, their role as zoonotic reservoirs and the large number of studies concerning parasites in urban dogs, rural areas in Brazil, especially those at the wildlife-domestic animal-human interface, have received little attention from scientists and public health managers. This paper reports a cross-sectional epidemiological survey of gastrointestinal parasites of rural dogs living in farms around Atlantic Forest fragments. Through standard parasitological methods (flotation and sedimentation), 13 parasite taxa (11 helminths and two protozoans) were found in feces samples from dogs. The most prevalent were the nematode Ancylostoma (47%) followed by Toxocara (18%) and Trichuris (8%). Other less prevalent (<2%) parasites found were Capillaria, Ascaridia, Spirocerca, Taeniidae, Acantocephala, Ascaris, Dipylidium caninum, Toxascaris, and the protozoans Cystoisospora and Eimeria. Mixed infections were found in 36% of samples, mostly by Ancylostoma and Toxocara. Previous deworming had no association with infections, meaning that this preventive measure is being incorrectly performed by owners. Regarding risk factors, dogs younger than one year were more likely to be infected with Toxocara, and purebred dogs with Trichuris. The number of cats in the households was positively associated with Trichuris infection, while male dogs and low body scores were associated with mixed infections. The lack of associations with dog free-ranging behavior and access to forest or villages indicates that infections are mostly acquired around the households. The results highlight the risk of zoonotic and wildlife parasite infections from dogs and the need for monitoring and controlling parasites of domestic animals in human-wildlife interface areas.

Gastrointestinal parasites of maned wolf (Chrysocyon brachyurus, Illiger 1815) in a suburban area in southeastern Brazil.

We examined 42 maned wolf scats in an unprotected and disturbed area of Cerrado in southeastern Brazil. We identified six helminth endoparasite taxa, being Phylum Acantocephala and Family Trichuridae the most prevalent. The high prevalence of the Family Ancylostomatidae indicates a possible transmission via domestic dogs, which are abundant in the study area. Nevertheless, our results indicate that the endoparasite species found are not different from those observed in protected or least disturbed areas, suggesting a high resilience of maned wolf and their parasites to human impacts, or a common scenario of disease transmission from domestic dogs to wild canid whether in protected or unprotected areas of southeastern Brazil.

High consumption of primates by pumas and ocelots in a remnant of the Brazilian Atlantic Forest.

We studied the diet of the ocelot and puma during the years 2007 and 2008 at the Feliciano Miguel Abdala Reserve, in Minas Gerais, south-eastern Brazil. We collected 49 faecal samples (scats) from cats, and identified the species of cat from 23 of them by the analysis of the microstructure patterns of hairs found in their faeces: 17 scats of the puma (Puma concolor) and six of the ocelot (Leopardus pardalis). In the puma scats, we identified three species of primates (Brachyteles hypoxanthus, Alouatta guariba and Sapajus nigritus), the remains of which were found in eight of 17 collected (47.1%), representing 26.7% of items consumed. For the ocelot, we detected capuchin monkey (S. nigritus) remains in three of the six scats (50%), accounting for 18.7% of items consumed by ocelot. We were unable to identify the cat species in the remaining 26 faecal samples, but we were able to analyse the food items present. Primates were found in five of these 26 faeces (19.2%) and represented 10.2% of the items found. Although the sample size is limited, our results indicate a relatively high consumption of primates by felines. We believe that this high predation may be the result of the high local density of primates as well as the greater exposure to the risks of predation in fragmented landscapes, which tends to increase the incidence of the primates using the ground.

Benznidazole treatment during early-indeterminate Chagas' disease shifted the cytokine expression by innate and adaptive immunity cells toward a type 1-modulated immune profile.

Trypanosoma cruzi-infected children was treated with benznidazole (Bz) during the early-indeterminate disease (E-IND) and the cytokine pattern of innate and adaptive immune compartments were evaluated prior to the treatment and 1 year after it. At first, we observed that the ex vivo cytokine profile of circulating leukocytes from E-IND (n = 6) resembled the one observed for healthy schoolchildren (n = 7). Additionally, in vitro stimulation with T. cruzi antigens drove the E-IND cytokine pattern toward a mixed immune profile with higher levels of IFN-gamma+, TNF-alpha+ and IL-4+ NK cells, increased numbers of IFN-gamma+, TNF-alpha+ and IL-10+ CD4+ T cells in addition to enhanced frequency of TNF-alpha+/IL-4+ CD19+ lymphocytes. Interestingly, upon T. cruzi antigen in vitro stimulation, E-IND CD8+ lymphocytes displayed a selective enhancement of IFN-gamma expression, accounting for a global type 1-modulated cytokine microenvironment. A shift toward a type 1-modulated profile was also the hallmark of Bz-treated children (E-IND(T)). In this context, despite the mixed overall ex vivo cytokine profile observed for NK and CD8+ T cells, increased ability of these leukocytes to produce IFN-gamma in response to T. cruzi antigens was reported. Most noteworthy was the IL-10 production evidenced at T lymphocytes, mainly CD4+ cells, as well as B lymphocytes, both ex vivo and upon antigen stimulation. Together, these findings gave evidence that NK cells and CD8+ T lymphocytes are the major sources of IFN-gamma, a pivotal cytokine for successful therapeutic response in human Chagas' disease. Moreover, our data have also brought additional information, pointing out IL-10 production by CD4+ cells and B lymphocytes, as the putative key element for parasite clearance in the absence of deleterious tissue damage.

Are increased frequency of macrophage-like and natural killer (NK) cells, together with high levels of NKT and CD4+CD25high T cells balancing activated CD8+ T cells, the key to control Chagas' disease morbidity?

The immunological response during early human Trypanosoma cruzi infection is not completely understood, despite its role in driving the development of distinct clinical manifestations of chronic infection. Herein we report the results of a descriptive flow cytometric immunophenotyping investigation of major and minor peripheral blood leucocyte subpopulations in T. cruzi-infected children, characterizing the early stages of the indeterminate clinical form of Chagas' disease. Our results indicated significant alterations by comparison with uninfected children, including increased values of pre-natural killer (NK)-cells (CD3- CD16+ CD56-), and higher values of proinflammatory monocytes (CD14+ CD16+ HLA-DR++). The higher values of activated B lymphocytes (CD19+ CD23+) contrasted with impaired T cell activation, indicated by lower values of CD4+ CD38+ and CD4+ HLA-DR+ lymphocytes, a lower frequency of CD8+ CD38+ and CD8+ HLA-DR+ cells; a decreased frequency of CD4+ CD25HIGH regulatory T cells was also observed. These findings reinforce the hypothesis that simultaneous activation of innate and adaptive immunity mechanisms in addition to suppression of adaptive cellular immune response occur during early events of Chagas' disease. Comparative cross-sectional analysis of these immunophenotypes with those exhibited by patients with late chronic indeterminate and cardiac forms of disease suggested that a shift toward high values of macrophage-like cells extended to basal levels of proinflammatory monocytes as well as high values of mature NK cells, NKT and regulatory T cells, may account for limited tissue damage during chronic infection favouring the establishment/maintenance of a lifelong indeterminate clinical form of the disease. On the other hand, development of an adaptive cell-mediated inflammatory immunoprofile characterized by high levels of activated CD8+ cells and basal levels of mature NK cells, NKT and CD4+ CD25HIGH cells might lead to late chronic pathologies associated with chagasic heart disease.