Clóvis de Paula Santos

Anthelmintic efficacy and management practices in sheep farms from the state of Rio de Janeiro, Brazil.

Anthelmintic resistance in parasites maybe a consequence of over-exposing populations of parasites to drugs or from the commerce/transit of animals harboring resistant parasites. Knowledge of the sensitivity of nematodes to anthelmintics is essential to establish an efficient integrated program of parasite control. In Brazil, producers rely on technology transfer from field professionals and non-technical labor for new management strategies of parasite control. The aim of this work was to determine the practices farmers used for anthelmintic management and to monitor drug efficacy on sheep farms from northern and northwestern regions of the state of Rio de Janeiro, Brazil. A questionnaire was sent to 34 farms, and anthelmintics were tested on ten of these farms. Sheep (n=10/group) were weighed and treated with albendazole, closantel, doramectin, fenbendazole, ivermectin, levamisole, moxidectin, or nitroxynil with their recommended doses. Faeces were collected on the day of treatment and after 7-10 days. The faecal egg count reduction test was evaluated based on RESO 2.0. Among the farmers interviewed, 97% applied commercial anthelmintics to control parasites, 77% rotated anthelmintics annually, 72% used ivermectin as the principal anthelmintic, and 38% applied anthelmintics with a frequency of 30-60 days. On two farms, none of the anthelmintics was efficacious. Levamisole had the best overall efficacy (70%). Albendazole, ivermectin, and fenbendazole were efficacious (above 95%) on only two farms. The present work illustrates the alarming lack of efficacy of drugs even in an area new to sheep farming. It is important to establish alternative strategies of management in a broad program of parasite control for reducing the selection pressure on parasites by the commercially available anthelmintics.

Prevalence of intestinal parasites versus knowledge, attitudes, and practices of inhabitants of low-income communities of Campos dos Goytacazes, Rio de Janeiro State, Brazil

Intestinal parasites are the causative agents of common infections responsible for significant public health problems in developing countries and generally linked to lack of sanitation, safe water, and improper hygiene. More than two billion people throughout the world live with unrelenting illness due to intestinal parasitic infections (IPIs). The purposes of this study are to assess knowledge, attitudes, and practices on IPIs and investigate the relationship with prevalence of intestinal parasites among a low-income group of inhabitants from two communities of the Travessão District area, Campos dos Goytacazes, north of Rio de Janeiro State, Brazil. The two communities are known as “Parque Santuário,” which is an urban slum with miserable living conditions, and “Arraial,” where the socioeconomic and educational levels are better, neither having a sanitary infrastructure with an excreta collection system. Questionnaires revealed that both communities had local and specific codification to denominate the intestinal parasites and present correct knowledge on the theme but ignored some aspects of IPI transmission, with the Arraial population being better informed (p < 0.05). The overall prevalence of IPIs in Parque Santuário (49.7%) was greater than in Arraial (27.2%) (p < 0.001; prevalence ratio/95% confidence interval 1.83/1.50–2.23). This study reports the real IPI situation in the Travessão District and also reinforces the need to continue the investigation on the impact of combined prophylactic methods, educational measures, and socioeconomic and sanitary improvements by governmental authorities and the local popular organization.

Morphological diagnosis of infective larvae of Libyostrongylus douglassii (Cobbold, 1882) Lane, 1923 and L. dentatus Hoberg, Lloyd and Omar, 1995 (Nematoda: Trichostrongylidae) of ostriches.

The differentiation of the species of the Libyostrongylus genus is only possible with the obtainment of the adult parasites in the ostriches proventriculus and gizzard. The present work confirms that it is possible to differentiate the infective larvae of L. douglassii and L. dentatus allowing the differential diagnosis of these species by fecal culture. To show this, adult females from both species were collected from ten proventriculus from adult ostriches and separated by species. Both groups were macerated individually added to sterilized feces for standard fecal cultures. The infective larvae were recovered, identified, quantified and measured. All proventriculus analyzed were parasitized by Libyostrongylus spp. and a clear heterogeneous location for each species was observed. The infective larvae from the fecal cultures of macerated L. douglassii presented a mean total length of 874.3+/-33.80 microm, and a short sheath tail (29.5+/-4.11 microm) with acute termination. The infective larvae from the macerated L. dentatus presented mean total length of 856.0+/-43.63 microm, long sheath tail (61.2+/-9.52 microm) with filamentous termination. The mean measures of the tails of both species had a significant difference. The differentiation of the infective larvae of L. douglassii and L. dentatus by fecal cultures will facilitate the diagnosis of both species for further understanding the Libyostrongylus biology.

Occurrence of nematodes and anthelmintic management of ostrich farms from different Brazilian states: Libyostrongylus douglassii dominates mixed infections

Ostriches were imported to Brazil in the early 1990s without appropriate parasite control leading to a co-importation of parasites. Libyostrongylus douglassii, Libyostrongylus dentatus and Codiostomum struthionis are nematodes of the ostriches that have been reported on some Brazilian farms but no national survey has been performed. Moreover, little is known about anthelmintic usage to control these parasites in Brazil. Therefore, the occurrence of L. douglassii, L. dentatus and C. struthionis and the anthelmintic management practices in Brazilian ostrich farms were studied. A questionnaire about management practices and information on how to collect, store and ship feces to the laboratory were sent to 17 farms located in 9 Brazilian states. Received fecal samples were submitted to fecal cultivation and larval harvested. Infective larvae were morphologically analyzed and quantified. The majority of the farms (88%) used an anthelmintic at least once a year. Ivermectin was the principal anthelmintic. Libyostrongylus sp. and C. struthionis were found in samples from 76 and 18% of the examined farms, respectively. The presence of L. douglassii (61-97%) was higher than L. dentatus (3-57%) and C. struthionis (2-30%). At the farm level, both species of Libyostrongylus were always found together. Sheath tail measurements of their infective larvae were crucial for morphological diagnosis. L. dentatus and L. douglassii are well adapted to Brazil and are widely distributed in the Brazilian territory, proving that this mixed infection in Brazilian ostrichs farms is common.

Helminths found in marmosets (Callithrix penicillata and Callithrix jacchus) introduced to the region of occurrence of golden lion tamarins (Leontopithecus rosalia) in Brazil

The introduction of exotic species can increase the risk of extinction of native species through the introduction of new diseases, predation or resource competition. The marmosets Callithrix penicillata and Callithrix jacchus and hybrids of these two species have been introduced to privately owned forests in the lowland Atlantic forest of the Rio de Janeiro State in Brazil, the region of occurrence of the endangered golden lion tamarin, Leontopithecus rosalia. Because the ecology and biology of the marmosets and tamarins is similar, there is a reasonable risk that the marmosets would transmit pathogens such as endo parasites. The objective of this study was to identify the helminth fauna present in the introduced marmosets through an analysis of fecal samples of wild caught animals, and to evaluate the parasitological profile according to age, sex and geographical location. Eggs belonging to the Acanthocephala and Nematoda were found in the feces. One nematode egg type was identified as being Primasubulura jacchi. The ocurrence of nematodes was higher in males, acanthocephala were found in all age groups and sexes and P. jacchi was found with higher frequency in adult females. The geographic distribution analysis revealed that some of the forests had a higher predominance of parasites. Little is known about the pathology of parasites in free living Neotropical mammals, and this knowledge would be necessary to infer about the risk (form a parasitological standpoint) that the marmoset presence represents for the survival of the endangered golden lion tamarin.

Nematophagous fungi in fresh feces of cattle in the Mata region of Minas Gerais state, Brazil

The capacity to survive gut passage is one of the desirable characteristics for nematophagous fungi to be considered potential biological control agents of gastrointestinal nematodes of livestock. From April 1995 to April 1996, a pool of 10 cow fecal samples and 10 individual samples of feces from heifers, which were raised under partial (cows) or total (heifers) confinement in the Mata Region of Minas Gerais State, Brazil, were examined monthly for the presence of nematophagous fungi. A total of 10 isolates was found in the survey. Eight isolates were recovered from the pooled samples of cow feces and two from the individual samples of heifers. Fungi were present in the cow feces during the dry months of August (two isolates of Arthrobotrys oligospora and one Monacrosporium eudermatum) and September (one isolate of Harposporium lilliputanum and one of M. gephyropagum). Fungi were also recovered at the beginning and middle of the rainy season: one isolate of A. musiformis in October, and one isolate of M. gampsosporum and one unidentified fungus which produced septate hyphae and adhesive buds in December. In the individual samples collected from heifers, fungi were present only in the months of September (end of dry season) and March (end of rainy season). One isolate each of H. lilliputanum and A. oligospora were found, respectively. Additional studies to further characterize these isolates should be encouraged.

Mixed infection with Libyostrongylus dentatusandLibyostrongylus douglassii induces a heterophilic inflammatory infiltrate in the proventriculus of ostriches

Libyostrongylus dentatus and Libyostrongylus douglassii are haematophagous nematodes found in the proventriculus and the ventriculus of ostriches. Pathological damage leading to bird death has been attributed to L. douglassii. However, histopathology of the mixed infection has not been reported. The aim of the present work was to characterize the cellular inflammatory infiltrate found in the proventriculus of ostriches with a mixed infection. Analysis of the collected nematodes confirmed a mixed infection in the proventriculus of examined birds. Histopathological examination of the proventriculus showed an inflammatory infiltrate composed of granular cells in close proximity to the nematodes. The granulocyte infiltrate was composed mainly of heterophils identified by the lack of peroxidase and presence of fusiform granules.

Efficacy of albendazole and moxidectin and resistance to ivermectin against Libyostrongylus douglassii and Libyostrongylus dentatus in ostriches.

Anthelmintic resistance has emerged globally as a problem amongst nematode of livestock and has been particularly well documented in equine and small ruminants. There are no studies regarding the efficacy of anthelmintics against the hematophagous nematodes in ostriches, Libyostrongylus dentatus; and just a few on L. douglassii. Here the efficacy of albendazole, ivermectin and moxidectin were evaluated against these two species in an ostrich farm in Minas Gerais state, Brazil. The feces were collected on the day of treatment and after 13 days of an oral dose of albendazole (6 mg/kg), or an injected dose (0.2mg/kg) of ivermectin or moxidectin. The fecal egg count reduction test and coprocultures were performed to determine possible resistance against the drugs used. An efficacy of 60% was found for ivermectin, while albendazole and moxidectin were 100% effective. Both worm species appeared to have reduced sensitivity to ivermectin.

Population dynamics of Libyostrongylus dentatus and L. douglassii of ostriches raised in the Northern Rio de Janeiro State, Brazil

Libyostrongylus genus contains three species of gastrointestinal nematodes that infect ostriches. Of these, only Libyostrongylus douglassii has been implicated in diseases and lower productivity. A morphological diagnosis method allowing the discrimination of infective larvae of L. douglassii and Libyostrongylus dentatus and the evaluation of eggs per gram of feces (EPG) was used to determine the population dynamics of both species from two ostrich farms located in the northern region of the state of Rio de Janeiro, Brazil. The presence of these nematodes was monitored every 15 days for two years. The average EPG was 4631 and 587 on farms 1 and 2, respectively. Overall, the highest values of EPG were associated with the rainy season on both farms. However, only on farm 1 the rainy season correlated statistically with EPG. Both species of Libyostrongylus occurred on both farms with a higher predominance (86%) of L. douglassii on farm 1, whereas the distribution of infection on farm 2 was more heterogeneous with a slight predominance of L. douglassii. The infection and the prevalence of these species may vary considerably according to the farm facilities, management adopted, and season.

The influence of health education on the prevalence of intestinal parasites in a low-income community of Campos dos Goytacazes, Rio de Janeiro State, Brazil

In a recent study by our group on the prevalence of intestinal parasitic infections and on the knowledge, attitudes and practices of local residents of Campos dos Goytacazes, Rio de Janeiro, Brazil, we observed that about 50% of the inhabitants were parasitized and had some knowledge of intestinal parasitic infections but did not apply this knowledge in daily practice. We were thus motivated to implement strategies in health education to promote preventive measures in the locality. The goal of the present work was to evaluate the influence of health education on the prevalence of intestinal parasitic infections in the region in an effort to strengthen public policies for controlling these diseases in Brazil. The methodology adopted was based on action-research and a theoretical framework of health promotion. Our results demonstrate that the study population exhibited an enhanced awareness of the importance of disease from intestinal parasitic infections. Attitudes and practices related to prevention were significantly improved after the shared health education. In conclusion, this study allowed the shared construction of knowledge that reflected the true needs of the residents.