Larvoscopic study on Dictyocaulus sp. in the faeces of beef cattle in northeastern Brazil / Estudo larvoscópico de Dictyocaulus sp. em fezes de bovinos de corte do nordeste do Brasil

Abstract The lungworm Dictyocaulus viviparus has an important role in cattle health and productivity worldwide, since infections can lead to substantial economic losses. Despite its importance, few studies investigating the epidemiological aspects of infection by this parasite have been conducted. The aim of this study was to report the occurrence of lungworm infection in beef cattle herds reared in an area of livestock production in the northeastern region of Brazil. From September 2020 to August 2021, monthly fecal samples (n = 493) were collected from 46 beef cattle. Among all the animals assessed, lungworm larvae were detected in 8.7% (4/46). None of them presented any clinical sign suggestive of infection by lungworm parasites. Twenty larvae were retrieved, with the minimum number (n = 1) detected in October and December, and the maximum number (n = 13) in November. These presented a mean length of 363 μm (± 28.65 μm) and mean width of 19 μm (± 1.03 μm), and were morphologically similar to Dictyocaulus sp.. This study reports the occurrence of this parasite in this livestock production area. Lastly, local veterinarians need to be aware of inclusion of this parasite in the differential diagnosis of other respiratory infections in beef cattle.

Resumo O parasito pulmonar Dictyocaulus viviparus tem um papel importante na saúde e produtividade bovina em todo o mundo, uma vez que infecções podem levar a perdas econômicas. Além de sua importância, poucos estudos que investigam aspectos epidemiológicos das infecções por esse parasito têm sido realizados. Objetivou-se, nesta pesquisa, relatar a ocorrência de infecção por nematódeos pulmonares em rebanhos bovinos de corte, criados em uma importante área de produção pecuária, na região Nordeste do Brasil. De setembro de 2020 a agosto de 2021, foram coletadas, mensalmente, amostras fecais (n = 493) de 46 bovinos de corte. De todos os animais avaliados, larvas de nematódeos pulmonares foram detectadas em 8,7% (4/46). Os animais não apresentaram nenhum sinal clínico sugestivo de infecção por parasitos pulmonares. Vinte larvas foram recuperadas, com o número mínimo (n = 1) detectado em outubro e dezembro, e o número máximo (n = 13) em novembro. Apresentavam comprimento médio de 363 μm (± 28,65 μm), largura média de 19 μm (±1,03 μm) e eram morfologicamente semelhantes a Dictyocaulus sp.. Este estudo relata a ocorrência desse parasito nesta área. Logo, os veterinários locais devem estar atentos à inclusão desse parasito no diagnóstico diferencial de outras infecções respiratórias em bovinos de corte.

Study on small ruminant lungworms and associated risk factors in northeastern Iran

OBJECTIVE@#To determine the prevalence, identify the species involved and assess possible risk factors of lungworm infection in small ruminant slaughtered in abattoir of Mashhad in the northeast of Iran from October 2010-August 2011.@*METHODS@#Faecal and post mortem examination were conducted on 350 and 2 500 animals, respectively.@*RESULTS@#The overall prevalence of lungworm infection was 10.85% and 3.80% in coproscopic and post mortem examination respectively, and this difference was found to be significant. Higher prevalence of lungworm infection was recorded in post mortem examination in sheep (4.1%) than in goats (0.5%) (P< 0.05). The proportion of infection with Dictyocaulus filaria, Protostrongylus rufescens and mixed infection were 3.7%, 0.1% and 0.2% in sheep while in goats, the infection was reported with Dictyocaulus filaria (0.5%) only. The seasonal dynamics of lungworm infection showed that prevalence was highest in winter (7.8%) with a remarkable decline during the dry time (summer) (0.8%) which the difference was significant (P<0.001). The animals of less than one year old showed greater infection in post mortem examination than older animals significantly (P<0.001). Also, the infection rate between male and female animals showed significant difference (P<0.05) with prevalence rate of 4.6% and 2.0%, respectively.@*CONCLUSIONS@#Due to its impact on production, emphasis should be given for the control and prevention of lungworm infection in this area.

Produtos de escreçäo e secreçäo de Dictyocaulus viviparus em diferentes meios de cultivo / Excretory-secretory products of Dictyocaulus viviparus in different culture media

Espécimes adultos de Dictyocaulus viviparus foram cultivados in vitro em diversos meios líquidos (RPMI, Tyrode e Ringer) para obtençäo de produtos de excreçäo e secreçäo. A análise estatística pelo teste t de Student para dados näo pareados mostrou näo haver diferença significativa entre o meio RPMI e o meio Tyrode, mas entre este último e o meio Ringer as diferenças foram evidentes. Pela eletroforese foram observadas bandas que oscilaram entre 94 e 20kDa, sendo as mais nítidas de 50,1; 39,8; 35,4; 30,0 e 28,1kDa em todos os meios estudados

Vascular permeability increasing action of the saline extract of Dictyocaulus filaria--a preliminary report.

The cutaneous hypersensitivity reaction in sheep infected with Dictyocaulus filaria was investigated. The saline extract of the worms increased the cutaneous capillary permeability in both the infected and uninfected control animals. Similar increase in the permeability was also observed in uninfected healthy rabbits. The results suggest that the vascular permeability increasing action of the worm extract is, partly, due to histamine release.