Daniele Bier

Lack of Cyathostomin sp. reduction after anthelmintic treatment in horses in Brazil.

The increase of anthelmintic resistance in the last years in the nematode population of veterinary importance has become a major concern. The objective of the present study was to evaluate the efficacy of the main anthelmintic drugs available in the market against small strongyles of horses in Brazil. A total of 498 horses from 11 horse farms, located in the states of Paraná, São Paulo, Rio de Janeiro and Minas Gerais, in Brazil, were treated with ivermectin, moxidectin, pyrantel and fenbendazole, orally at their recommended doses. The fecal egg count reduction test (FECRT) was used to determine the products efficacy and fecal culture was used to determine the parasite genus. Reduction on anthelmintic efficacy was found for fenbendazole in all horse farms (11/11), pyrantel in five yards (5/11) and ivermectin had low efficacy in one of the yards studied (1/11). Multidrug resistance of up to 3 drugs classes was found in one of the tested farms (1/11). Cyathostomin were the most prevalent parasite. The results showed that resistance to fenbendazole is widespread; the efficacy of pyrantel is in a critical situation. Although the macrocyclic lactones compounds still showed high efficacy on most farms, suspected resistance to macrocyclic lactones is of great concern.

Cat infected by a variant of bat rabies virus in a 29-year disease-free urban area of southern Brazil

INTRODUCTION After 29 years, rabies was detected in a cat in Curitiba, southern Brazil. METHODS The fluorescent antibody test (FAT) and mouse inoculation test (MIT) were performed on central nervous system (CNS) samples. RESULTS Direct immunofluorescence was negative, but the biological test was positive and rabies virus was characterized as variant 4 (from Tadarida brasiliensis). CONCLUSIONS Reappearance of rabies in domestic animals warns of sylvatic-aerial risk of infection and the necessity of monitoring bats in historically rabies-free areas.

Evaluation of resistance in a selected field strain of Haemonchus contortus to ivermectin and moxidectin using the Larval Migration on Agar Test

Haemonchus contortus e uma das causas mais comuns e economicamente significativas de doenca em producoes de pequenos ruminantes em todo o mundo, e os programas de controle de parasitas nematoides - incluindo H. contortus - baseiam-se principalmente no uso de drogas anti-helminticas. A consequencia da utilizacao desses compostos, como sendo a unica estrategia sanitaria para evitar infeccoes por parasitas, tem sido a reducao da eficacia de todos os produtos quimioterapicos, selecionando fortemente para resistencia. O desenvolvimento generalizado da resistencia anti-helmintica e a dificuldade de seu diagnostico precoce tem sido uma grande preocupacao para o manejo sustentavel de parasitas no campo. O objetivo desta pesquisa foi determinar e comparar o efeito da ivermectina (IVM) e da moxidectina (MOX) em um isolado de campo selecionado de H. contortus com um estado de resistencia conhecido, utilizando o teste in vitro de migracao de larvas em agar (LMTA). Larvas de terceiro estagio de um isolado de H. contortus selecionado foram obtidas a partir de culturas de fezes de ovinos infectados experimentalmente e incubadas em onze concentracoes diluidas crescentes de IVM e MOX (6, 12, 24, 48, 96, 192, 384, 768, 1536, 3072 e 6144µg/mL). As curvas sigmoides de dose-resposta foram obtidas utilizando o valor de R2 >0,90 e a dose de concentracao letal (CL50) para as drogas anti-helminticas testadas, utilizando um modelo logistico de quatro parâmetros. O valor de CL50 para MOX foi significativamente menor do que para IVM (1,253µg/mL e 91,06µg/mL), identificando o isolado de H. contortus como consideravelmente menos suscetivel a IVM em comparacao a MOX. Alem disso, o LMTA mostrou uma alta consistencia (p<0,0001) e pode ser uma ferramenta util de diagnostico para monitorar o status de resistencia de IVM e MOX em isolado de campo de H. contortus, assim como ser utilizado de forma oficial e em rotina para programas de monitoramento das drogas sob a demanda do Ministerio da Agricultura (MAPA).

Dog parasite incidence and risk factors, from sampling after one-year interval, in Pinhais, Brazil

Domestic animals in urban areas may serve as reservoirs for parasitic zoonoses. The aim of this study was to monitor the parasitic status of household dogs in an urban area of Pinhais, in the metropolitan region of Curitiba, Paraná State, Brazil, after a one-year period. In May 2009, fecal samples, skin scrapings and ticks were collected from 171 dogs. Questionnaires were applied to the owners (sex, age, environment and anthelmintic use). In May 2010, 26.3% (45/171) of the dogs were fecal samples re-analysed. From the fecal samples, 33.3% (57/171) in 2009 and 64.4% (29/45) in 2010 were positive. The parasite species most observed were, respectively in 2009 and 2010, Ancylostoma sp., 66.7 and 44.8%, and Strongyloides stercoralis, 26.3 and 3.4%. All the skin scrapings were negative, and no ticks or protozoa were found. There was no statistical association (p > 0.05) between positive fecal tests and age, sex or environment. In 2009 alone, dogs with a history of antiparasitic drug administration were 2.3 times more likely to be negative. A great number of replacement dogs was noticed one year later. Therefore, isolated antiparasitic treatment strategies may have no impact on parasite control, given the risk of introduction of new agents, thereby limiting the prevention strategies.

Análise espacial do risco de leptospirose canina na Vila Pantanal, Curitiba, Paraná

Leptospirosis is a serious zoonotic disease associated to low income areas of urban settings. Although rodents are considered the main reservoir for urban leptospirosis, dogs may also develop the disease and become asymptomatic carriers. The objective of this study was to apply a statistical method based on the spatial point processes theory for canine leptospirosis to identify how seroreagents dogs are spatially distributed and their risk determinants in a village of Curitiba city. The model analysis allowed the identification of over-risk regions, where seropositivity risk for canine leptospirosis was significantly higher, revealing that not just one, but the combination of animal, owner and environment factors influenced the disease risk within areas with greater spatial effect. Analysis of results clearly identified the highest risk areas in the Pantanal Village, allowing the establishment of more specific preventive actions and focused on risk areas as priority for public health surveillance.

Seroprevalence and seroincidence of Leptospira infection in dogs during a one-year period in an endemic urban area in Southern Brazil

INTRODUCTION Leptospirosis is a zoonosis that affects both humans and animals. Dogs may serve as sentinels and indicators of environmental contamination as well as potential carriers for Leptospira. This study aimed to evaluate the seroprevalence and seroincidence of leptospirosis infection in dogs in an urban low-income community in southern Brazil where human leptospirosis is endemic. METHODS A prospective cohort study was designed that consisted of sampling at recruitment and four consecutive trimestral follow-up sampling trials. All households in the area were visited, and those that owned dogs were invited to participate in the study. The seroprevalence (MAT titers ≥100) of Leptospira infection in dogs was calculated for each visit, the seroincidence (seroconversion or four-fold increase in serogroup-specific MAT titer) density rate was calculated for each follow-up, and a global seroincidence density rate was calculated for the overall period. RESULTS A total of 378 dogs and 902.7 dog-trimesters were recruited and followed, respectively. The seroprevalence of infection ranged from 9.3% (95% CI; 6.7 - 12.6) to 19% (14.1 - 25.2), the seroincidence density rate of infection ranged from 6% (3.3 - 10.6) to 15.3% (10.8 - 21.2), and the global seroincidence density rate of infection was 11% (9.1 - 13.2) per dog-trimester. Canicola and Icterohaemorraghiae were the most frequent incident serogroups observed in all follow-ups. CONCLUSIONS Follow-ups with mean trimester intervals were incapable of detecting any increase in seroprevalence due to seroincident cases of canine leptospirosis, suggesting that antibody titers may fall within three months. Further studies on incident infections, disease burden or risk factors for incident Leptospira cases should take into account the detectable lifespan of the antibody.