Oestrus ovis infection of grazing sheep during summer in southern Chile

Prevalence Rate and Molecular Characteristics of Oestrus ovis L. (Diptera, Oestridae) in Sheep and Goats from Riyadh, Saudi Arabia

Heads of sheep (n = 600) and goats (n = 800) slaughtered at Al-Aziziah Abattoir in Riyadh, Saudi Arabia, were inspected for the presence of O. ovis larvae (L). Heads were split along the longitudinal axes, and larvae (L1, L2, and L3) were gathered. The infestation rate was significantly higher in goats (44.5%; 356/800) than that in sheep (22.3%; 134/600). Out of the 151 collected larvae from sheep, 0% were L1, 1.3% were L2, and 98.7% were L3. Out of the total of 468 larvae from goats, 0% were L1, 1.2% were L2, and 98.8% were L3. The infestation rate was significantly higher in males than that in females. Myiasis-causing larvae collected from Riyadh, Saudi Arabia, were authenticated as O. ovis, according to morphological characteristics. Polymerase chain reaction (PCR) amplification of a partial fragment (600 bp) of the mitochondrial cytochrome c oxidase subunit I (mtCOI) gene further confirmed the species. Phylogenetic analysis based on the partial mtCOI gene sequence demonstrated that 23 unique sequences showed high similarity based on nucleotide pairs of O. ovis accessions retrieved from GenBank.

Prevalence of Oestrus ovis (Diptera: Oestridae) in sheep from Ituiutaba, south-east region of Brazil

Abstract Among the diseases which can afflict the nasal cavities of small ruminants, oestrosis stands out. In Brazil, more specifically in its South-East region, the reports are limited only to the State of São Paulo and to the municipality of Araxá, Minas Gerais. Therefore, it has been sought to assess the parasitic prevalence of Oestrus ovis in sheep farmed in the municipality of Ituiutaba, Minas Gerais-Brazil, while correlating the larval size and stage, and its anatomical localization. Eighty-eight hemiheads of healthy Santa Inês/Dorper crossbreds Ovis aries have been used at random. The larvae in view were then collected and fixated to be quantified and analyzed in regard of size and stage of development. It is concluded that the oestrosis is an existing problem in the municipality of Ituiutaba, this being the first complete study on the prevalence of this parasite in the State of Minas Gerais. By anatomical distribution, only the differences of total larval averages between the frontal sinus and the ventral nasal meatus, the common nasal meatus and the nasopharynx have been significant. In size, the significant difference has been there only upon comparison between the size and the larval stage, information that is crucial for a better understanding of the cyclic progression, of the clinical symptomatology, and animal prophylaxis.

Evaluation of tumor necrosis factor-alpha (TNF-α); gamma interferon (IFN-γ) genes and oxidative stress in sheep: immunological responses induced by Oestrus ovis (Diptera: Oestridae) infestation

This study aimed to evaluate the cell mediated immune responses against Oestrus ovis (O. ovis) in sheep through measurement of the changes in mRNA expression of the tumor necrosis factor alpha (TNF-α) and gamma interferon (IFN-γ) cytokines using quantitative Real time-PCR (qRt-PCR). Also; to detect the role of Oestrus ovis infestation in the oxidative stress markers in sheep. Fifty sheep head were examined in Cairo abattoir from the period of May to August 2019. Sera were separated and collected for measurement of nitric oxide, zinc and malondialdehyde (MDA). While TNF-α and IFN-γ mRNA were extracted from nasal mucosa. Levels of IFN-γ and TNF-α were significantly higher in infested sheep than that in non-infested one. Also, oxidative stresses were indicated by high level of nitric oxide as one of reactive oxygen species (ROS) and serum MDA as oxidative stress marker and low antioxidant capacity (zinc concentration in serum) in infested sheep. The obtained results indicated that measurements of TNF-α and IFN-γ cytokines using qRT-PCR could be used as an association and reproducible quantitative method for the diagnosis of O. ovis infestation in sheep.

The global and regional prevalence of oestrosis in sheep and goats: a systematic review of articles and meta-analysis

Background

Oestrosis, caused by the larvae of Oestrus ovis, commonly known as sheep nose bot, is an obligatory cavitary myiasis of sheep and goats. Oestrus ovis is a widespread parasite, but little is known about the prevalence of oestrosis at the global and broad geographical levels. The present study aimed to explore the epidemiology of oestrosis at the global and regional level to estimate prevalences and their associated factors using a systematic approach. This is, to the author’s knowledge, the first meta-analysis of oestrosis in sheep and goats.

Methods

Published articles were obtained from nine electronic databases (PubMed, CAB Abstracts, Web of Science, Scopus, UCB library, Medline, Biosis Citation Index, Indian journals and Google Scholar) reporting the prevalence of O. ovis in sheep and goats from 1970 to 2018. Pooled prevalences were estimated using a random effect meta-analysis model.

Results

Sixty-six studies were eligible, and data from 40,870 sheep and 18,216 goats were used for quantitative analysis. The random effect estimated prevalence of oestrosis at the global level in sheep was 51.15% (95% CI: 42.80–59.51%) and in goats was 42.19% (95% CI: 33.43–50.95%). The pooled prevalence estimates for Africa, Asia, Europe and the Americas were 47.85% (95% CI: 36.04–59.66%), 44.48% (95% CI: 33.09–55.87%), 56.83% (95% CI: 48.92–64.74%) and 34.46% (95% CI: 19.90–49.01%), respectively. Heterogeneity (I² > 80%) was detected in most pooled estimates.

Conclusions

Oestrosis is highly prevalent in many geographical regions of the world, especially in Europe and Africa. Factors that contribute to the pooled prevalence estimate of oestrosis need to be emphasised in any survey to estimate the true prevalence of oestrosis. Furthermore, there is a need for immunisation or implementation of other preventive measures to reduce the burden of oestrosis in sheep and goats and to improve the health and welfare status.

Electronic supplementary material

The online version of this article (10.1186/s13071-019-3597-2) contains supplementary material, which is available to authorized users.

Oestrus ovis in Ecuador: Importance in the Andean sheep farming

Aim

This study aimed to determine the prevalence of Oestrus ovis in sheep meant for meat commercialization in the main slaughterhouse of the country.

Materials and Methods

Between October 2015 and December 2015, we assessed the occurrence of Oestrus myiasis in the main slaughterhouse localized in Quito. In total, 80 sheep heads were randomly inspected and necropsied. Larvae were removed from nasal cavities and paranasal sinuses and cleaned. ANOVA (generalized linear model) was used to estimate the relationship between sex, age, and place of origin and presence or absence of parasite larvae.

Results

Morphological identification confirmed that 19% (15/80) of the examined animals were positive for Oestrus ovis; from the positive cases, 21% were young animals <12 months old. We found that statistical differences by animal sex, males, were most infested 93% (14/15) than females 7% (1/15). Larvae's L2 were more abundant than other stages (62 of the total 149). 14 of the infested animals were from the Andean places at > 2500 meters above sea level (m.a.s.l.), and only one case from the coastal region at 250 m.a.s.l. with tropical environmental conditions.

Conclusions

Our results showed evidence of the presence of myiasis caused by O. ovis in Andean and coastal places in Ecuador and its adaptation to different environmental conditions from that reported previously in temperate regions from Europe and Africa.

Immune humoral response of young lambs naturally infested by Oestrus ovis (Diptera: Oestridae)

Twenty-six newborn lambs were evaluated for 21 weeks, from birth to slaughter, to assess their plasma anti-Oestrus ovis immunoglobulin (IgG) using the ELISA technique. On the last day of sampling, all the lambs were slaughtered and O. ovis larvae were recovered, quantified and identified according to the larval stage. High levels of IgG were observed over the first three weeks of life, thus indicating that antibodies are transferred via colostrum from ewes to lambs. Afterwards, the antibody levels declined progressively until the lambs were 11 weeks of age and subsequently started to increase again when they were around 13 weeks of age, reaching the apex on the last week of sampling. All the lambs were parasitized with different larval stages of O. ovis, with an average of 39 larvae per lamb, and the intensity of the infestation ranged from 10 to 97 larvae. However, there was non-significant correlation coefficients between IgG levels and O. ovis larval burden (P > 0.05). In conclusion, although the lambs became infested with O. ovis at an early age, the larval burden was not associated with specific IgG levels.