Neospora caninum and Toxoplasma gondii as causes of reproductive losses in commercial sheep flocks from Argentina

Rosa, Paola Della; Fiorentino, Marí­a Andrea; Morrell, Eleonora; Scioli, María V.; Paolicchi, Fernando Alberto; Moore, D.P.; Cantón, Germán; Hecker, Yanina P.

doi:10.1016/j.crpvbd.2021.100057

Cited by 7 publications

(7 citation statements)

References 41 publications

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“…The absence of N. caninum DNA in all the tested samples is consistent with a serological survey conducted in 2008 in 10 randomly-selected sheep flocks in three departments of Uruguay (Artigas, Salto, Canelones), which indicates a low N. caninum seroprevalence in this species ( 26 ). These findings are surprising for several reasons: (1) neosporosis is widely distributed in cattle herds in Uruguay, and is the main infectious cause of abortion identified at the laboratory level ( 31 , 74 ); (2) N. caninum was recently reported to be a cause of abortion in flocks in the central region of Argentina, which shares similar productive, geographical, and climatic conditions with Uruguay ( 75 ); and (3) the common utilization of shepherd and/or guardian dogs in sheep flocks in Uruguay, which warrants a close contact between the protozoan's definitive hosts (canids) and the susceptible intermediate hosts (ruminants). The extensive conditions sheep are usually reared under ( 76 ), the low number of animals per flock ( 77 ) or the pasture-based instead of concentrate-based diets ( 78 ), could account for the low prevalence of neosporosis.…”

Section: Discussionmentioning

confidence: 99%

Diagnostic Investigation of 100 Cases of Abortion in Sheep in Uruguay: 2015–2021

et al. 2022

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The aim of this work was to identify causes of abortion through laboratory investigations in sheep flocks in Uruguay. One hundred cases of abortion, comprising 58 fetuses, 36 fetuses with their placentas, and 6 placentas were investigated in 2015–2021. Cases were subjected to gross and microscopic pathologic examinations, and microbiological and serological testing for the identification of causes of abortion, including protozoal, bacterial, and viral pathogens. An etiologic diagnosis was determined in 46 (46%) cases, including 33 (33%) cases caused by infectious pathogens, as determined by the detection of a pathogen along with the identification of fetoplacental lesions attributable to the detected pathogen. Twenty-seven cases (27%) were caused by Toxoplasma gondii, 5 (5%) by Campylobacter fetus subspecies fetus, and 1 (1%) by an unidentified species of Campylobacter. Fourteen cases (14%) had inflammatory and/or necrotizing fetoplacental lesions compatible with an infectious etiology. Although the cause for these lesions was not clearly identified, T. gondii was detected in 4 of these cases, opportunistic bacteria (Bacillus licheniformis, Streptococcus sp.) were isolated in 2 cases, and bovine viral diarrhea virus 1 subtype i (BVDV-1i) was detected in another. Campylobacter jejuni was identified in 1 (1%) severely autolyzed, mummified fetus. BVDV-2b was identified incidentally in one fetus with an etiologic diagnosis of toxoplasmosis. Microscopic agglutination test revealed antibodies against ≥1 Leptospira serovars in 15/63 (23.8%) fetuses; however, Leptospira was not identified by a combination of qPCR, culture, fluorescent antibody testing nor immunohistochemistry. Neospora caninum, Chlamydia abortus, Chlamydia pecorum, Coxiella burnetii and border disease virus were not detected in any of the analyzed cases. Death was attributed to dystocia in 13 (13%) fetuses delivered by 8 sheep, mostly from one highly prolific flock. Congenital malformations including inferior prognathism, a focal hepatic cyst, and enterohepatic agenesis were identified in one fetus each, the latter being the only one considered incompatible with postnatal life. Toxoplasmosis, campylobacteriosis and dystocia were the main identified causes of fetal losses. Despite the relatively low overall success rate in establishing an etiologic diagnosis, a systematic laboratory workup in cases of abortion is of value to identify their causes and enables zoonotic pathogens surveillance.

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Section: Discussionmentioning

confidence: 99%

Diagnostic Investigation of 100 Cases of Abortion in Sheep in Uruguay: 2015–2021

et al. 2022

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“…The economic losses of ruminant's reproductive failure caused by N. caninum infection worldwide are estimated at 1.3 billion dollars annually ( 22 ); therefore, its role in the abortion of sheep and goats should not be ignored. To diagnose N. caninum infection in aborted fetuses, the researchers have worked on diagnostic methods with different sensitivities and specificities, such as histopathology ( 23 ), immunohistochemistry (IHC) ( 24 ), serology ( 25 ), and polymerase chain reaction (PCR) ( 26 ). There are limited studies on the prevalence of N. caninum infection in the aborted fetuses of sheep and goats.…”

Section: Introductionmentioning

confidence: 99%

The Global Prevalence of Neospora caninum Infection in Sheep and Goats That Had an Abortion and Aborted Fetuses: A Systematic Review and Meta-Analysis

et al. 2022

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Neospora caninum (N. caninum) can be a potential factor causing a significant rate of miscarriages in small ruminants (sheep and goats) worldwide. Therefore, the present study aimed to determine the global status of N. caninum in sheep and goats that had an abortion and aborted fetuses. Five English databases (PubMed, ScienceDirect, Web of Science, Scopus, and ProQuest) were searched for relevant scientific articles published from their inception until November 4, 2021. Finally, 21 studies conducted on sheep (1,671 aborted fetuses and 935 abortive sheep) and 10 studies on goats (130 aborted fetuses and 80 abortive goats) were included for the final meta-analysis. A random-effects meta-analysis model was used to estimate the pooled prevalence with 95% confidence intervals (CIs). Moreover, sensitivity analysis, publication bias test, and quality assessment were performed in this study. The pooled prevalence of N. caninum in aborted fetuses of sheep and goats globally was estimated to be 15% (95% CI: 9–21%) and 7% (95% CI: 2–12%) using molecular methods. Besides, the seroprevalence of N. caninum was estimated to be 17% for aborted fetuses of sheep. The overall prevalence rate of N. caninum infection in sheep that had an abortion was 3%. The present results show a relatively high prevalence of N. caninum infection in sheep that had an abortion and aborted fetuses compared to goats. Therefore, further studies using different diagnostic techniques to more accurately estimate the rate of infection in sheep and goats may help provide adequate control measures and strategies to reduce the rate of abortion in sheep and goats and reduce economic damage to the livestock industry. This study was registered at the International Prospective Register of Systematic Reviews (PROSPERO; code: CRD42020216694).

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“…Neospora caninum is well recognised as a major abortifacient in cattle ( Dubey et al, 2017 ) and although it seems to have a lower clinical and economic importance in small ruminants, there is increasing evidence of its involvement in cases of abortion and reproductive failure both in sheep and goats worldwide ( Moreno et al, 2012 ; Della Rosa et al, 2021 ; Sánchez-Sánchez et al, 2021a , Sánchez-Sánchez et al, 2021b ; Unzaga et al, 2014 ; Dubey et al, 2017 ; Hässig et al, 2003 ).…”

Section: Discussionmentioning

confidence: 99%

Toxoplasma gondii and Neospora caninum infections in sheep and goats in Switzerland: Seroprevalence and occurrence in aborted foetuses

Basso

Fabienne²,

Schares³

et al. 2022

Food and Waterborne Parasitology

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Neospora caninum and Toxoplasma gondii as causes of reproductive losses in commercial sheep flocks from Argentina

Cited by 7 publications

References 41 publications

Diagnostic Investigation of 100 Cases of Abortion in Sheep in Uruguay: 2015–2021

Diagnostic Investigation of 100 Cases of Abortion in Sheep in Uruguay: 2015–2021

The Global Prevalence of Neospora caninum Infection in Sheep and Goats That Had an Abortion and Aborted Fetuses: A Systematic Review and Meta-Analysis

Toxoplasma gondii and Neospora caninum infections in sheep and goats in Switzerland: Seroprevalence and occurrence in aborted foetuses

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