A holstein heifer infected with Neospora caninum NcUru3 congenitally transmits this strain to a viable offspring although infection does not protect her from aborting by a different N. caninum genotype in the subsequent gestation.

Neospora caninum is a leading cause of bovine abortion worldwide. Although the genetic diversity of this apicomplexan parasite has long been recognized, there is little information on whether infection with different genotypes results in different clinical outcomes or whether infection by a given genotype impairs protective immunity against abortion induced by different genotypes. Here, we provide evidence supporting that natural subclinical infection with isolate NcUru3 of N. caninum in a pregnant heifer did not provide protection against abortion caused by a different N. caninum genotype in the subsequent gestation. A Holstein heifer delivered a healthy calf congenitally infected with N. caninum. Specific anti-N. caninum IgG was detected by indirect ELISA in sera obtained from the dam at calving and the calf before ingestion of colostrum, indicating in utero exposure to the parasite in the latter. A N. caninum strain named NcUru3 was isolated and characterized by multilocus microsatellite typing from the brain of this neonate euthanized at 9 days of age. Sixty days after calving, the cow got pregnant, although she aborted spontaneously at ~6 months of gestation. Pathologic examination of the aborted fetus and placenta revealed typical lesions of neosporosis, including encephalitis, myocarditis, hepatitis, myositis, and placentitis. Neospora caninum DNA was amplified from the fetal brain, heart, kidney, and placenta, and multilocus microsatellite typing revealed a genotype that differed from isolate NcUru3 at the level of microsatellite marker 6A (MS6A). Serum obtained from the dam at the time of abortion had IgG that cross-recognized isolate NcUru3, as demonstrated by immunoblotting, indicating that the humoral immune response did not prevent the other genotype from infecting the fetus and inducing fetoplacental lesions and abortion. This is the first description of one same dam transmitting two N. caninum genotypes to her offspring in subsequent gestations.

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

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.

Placentitis and abortion caused by a multidrug resistant strain of Campylobacter fetus subspecies fetus in a sheep in Uruguay / Placentitis y aborto causado por una cepa de Campylobacter fetus subespecie fetus multirresistente a antibióticos en una oveja en Uruguay

Abstract Campylobacter fetus fetus (Cff) is a major infectious cause of abortion in sheep worldwide, and an opportunistic human pathogen. Information on Cff as an ovine abortifacient in South America is limited. We describe a case of abortion caused by a multidrug resistant strain of Cff in a sheep in Uruguay. In August 2017, 3/57 pregnant ewes (5.3%) aborted whithin one week. Histopathologic examination of the placenta of an aborted ewe revealed severe neutrophilic and fibrinonecrotizing placentitis with vasculitis and thrombosis of the chorionic arterioles. Cff was isolated on microaerobic culture in Skirrow agar, and further confirmed by 16S rDNA PCR amplification and sequencing, and endpoint and real time PCR assays. Antimicrobial sensitivity testing revealed resistance to tetracyclines, nalidixic acid, telithromycin and clindamycin. Other abortifacients were not detected. Further studies are necessary to determine the geographic distribution, ecology, epidemiology, economic impact, and antimicrobial resistance of Cff in sheep flocks in Uruguay.

Resumen Campylobacter fetus fetus (Cff) es una importante causa de abortos en ovinos y un patógeno oportunista en humanos. La información sobre Cff como abortifaciente en ovinos en Sudamérica es limitada. Describimos un caso de aborto causado por una cepa de Cff mul tirresistente a antibióticos en una oveja en Uruguay. En agosto de 2017, 3/57 ovejas prenadas (5,3%) abortaron en una semana. El examen histopatológico de la placenta de una de ellas reveló placentitis neutrofílica fibrinonecrosante severa, vasculitis y trombosis. Cff fue aislado en microaerobiosis en agar Skirrow, y confirmado mediante amplificación del ADNr 16S por PCR seguida de secuenciación, y por PCR punto final y qPCR. Las pruebas de sensibilidad antimicrobiana revelaron resistencia a tetraciclinas, ácido nalidíxico, telitromicina y clindamicina. No se detectaron otros abortifacientes. Son necesarios más estudios para determinar la distribución geográfica, ecología, epidemiología, el impacto económico y la resistencia antimicrobiana de Cff en majadas ovinas de Uruguay.

Placentitis and abortion caused by a multidrug resistant strain of Campylobacter fetus subspecies fetus in a sheep in Uruguay.

Campylobacter fetusfetus (Cff) is a major infectious cause of abortion in sheep worldwide, and an opportunistic human pathogen. Information on Cff as an ovine abortifacient in South America is limited. We describe a case of abortion caused by a multidrug resistant strain of Cff in a sheep in Uruguay. In August 2017, 3/57 pregnant ewes (5.3%) aborted whithin one week. Histopathologic examination of the placenta of an aborted ewe revealed severe neutrophilic and fibrinonecrotizing placentitis with vasculitis and thrombosis of the chorionic arterioles. Cff was isolated on microaerobic culture in Skirrow agar, and further confirmed by 16S rDNA PCR amplification and sequencing, and endpoint and real time PCR assays. Antimicrobial sensitivity testing revealed resistance to tetracyclines, nalidixic acid, telithromycin and clindamycin. Other abortifacients were not detected. Further studies are necessary to determine the geographic distribution, ecology, epidemiology, economic impact, and antimicrobial resistance of Cff in sheep flocks in Uruguay.

Complete Genome Sequence of Campylobacter fetus Isolated from a Sheep.

Campylobacter fetus is an important reproductive pathogen of ruminants that occasionally infects humans. Here, we describe the complete circularized genome of a strain of Campylobacter fetus subsp. fetus isolated from a sheep. The final assembly consisted of a unique contig with a length of 1,849,237 bp.

Baccharis coridifolia poisoning in livestock in Uruguay.

Baccharis coridifolia is one of the most common poisonous plants affecting livestock in Uruguay. Poisoning occurs when animals raised in areas free of B. coridifolia are transported to pastures containing the plant. Young stock become spontaneously averted to it after ingesting non-toxic amounts of the plant. As B. coridifolia is widespread in the country, farmers selling livestock report when animals have been raised in areas with the plant, meaning that they are naturally averted and will not ingest it if introduced in B. coridifolia-containing paddocks. Of 2456 farmers from 18 departments of Uruguay selling cattle through online auctions between June 2019 and May 2020, 78% mentioned that the animals they were selling were raised in grasslands containing B. coridifolia. However, only 35.8% of the farmers from three departments of Eastern Uruguay mentioned that their cattle were raised in grasslands with B. coridifolia. Herds from these departments presented 16.7 times (95% CI: 13.1-21.3; p < 0.001) more risk of not being naturally averted to B. coridifolia ingestion than the herds of the other 15 departments of the country. In this paper we review all outbreaks of B. coridifolia poisoning reported in livestock in Uruguay from 1911 to present. We also describe three outbreaks of poisoning, one in cattle and two in sheep that were poisoned in the same farms in which the animals were raised. Intoxication occurred when the animals raised indoors and/or in cultivated pastures without B. coridifolia were introduced into grasslands of the same farms containing B. coridifolia. Typical gastrointestinal lesions were observed in pathological examinations. Furthermore, two of three necropsied heifers showed severe acute nephrosis, which had not been reported previously in this poisoning.

Diseases associated with bovine viral diarrhea virus subtypes 1a and 2b in beef and dairy cattle in Uruguay.

Bovine viral diarrhea virus (BVDV, Pestivirus) causes significant economic losses to the livestock industry worldwide. Although serological surveys show that BVDV exposure is widespread in cattle in Uruguay, BVDV-associated diseases are greatly underreported. The aim of this work is to describe the epidemiological, clinical, pathological, and virological findings from spontaneous outbreaks of BVDV-associated diseases in cattle in Uruguay. Diagnostic investigations were performed during 6 spontaneous disease outbreaks on beef and dairy cattle farms in the departments of Colonia, Rio Negro, and Soriano between November 2016 and April 2018. Carcasses of 8 naturally deceased cattle from these outbreaks were necropsied and subjected to histological examination and immunohistochemistry to detect BVDV antigen in the tissues. Reverse transcription real-time PCR and genomic sequencing were also performed to identify BVDV at the species and subtype levels. Other ancillary diagnostic tests, including bacterial cultures, were performed on a case-by-case basis to rule in/out differential diagnoses based on initial clinicopathological presumptive diagnoses. BVDV-associated conditions that were diagnosed in the 8 cases included mucosal disease, transient postnatal BVDV infections associated with digestive/septicemic salmonellosis by Salmonella serovar typhimurium, Histophilus somni bronchopneumonia, urinary tract coinfections with Escherichia coli and Streptococcus sp., enteric coinfection with coccidia, and transplacental fetal infections and abortions with Neospora caninum coinfection. BVDV-1a and BVDV-2b were each identified in four of the eight cases. We conclude that BVDV-1a and BVDV-2b contribute significantly to disease and mortality in cattle in Uruguay. Future research should estimate the economic impact of BVDV in the Uruguayan livestock sector.

Rhipicephalus microplus, babesiosis and anaplasmosis in Uruguay: current situation and control or elimination programs on farms.

Rhipicephalus microplus causes high economic losses for Uruguay; the country is divided into a R. microplus-free area and an endemic area. The aim of this research was to evaluate the R. microplus and tick fever situation in Uruguay and the feasibility of implementing R. microplus control or elimination programs to reduce the number of infested farms. A representative survey was performed to determine the number of infested farms, the number of farms with outbreaks of tick fever and the control and preventive measures being used. Control or elimination programs using generational treatment were implemented on 30 farms. Previously, a situation diagnosis was performed by evaluating the background of each farm, identifying acaricide resistance, serologically evaluating the enzootic stability of tick fever, and analyzing the risk of R. microplus introduction to farms. According to the survey, R. microplus was present on 9544 (36%) farms, and 3436 (36%) of these farms experienced outbreaks of tick fever. Only 323 (9.4%) farmers used the tick fever vaccine. Of the 30 farms for which control or elimination programs were carried out, 18 reduced the number of treatments applied per year and six achieved the elimination of the cattle tick. It is concluded that by administering elimination or control programs, it is possible to reduce the number of infested farms and the number of treatments to maintain control. New surveys should be performed to measure the degree of technology adoption by farmers and to analyze the advances in tick control or elimination programs on farms.

Fatal Sarcocystis cruzi-induced eosinophilic myocarditis in a heifer in Uruguay.

Sarcocystis spp. are causative agents of bovine eosinophilic myositis and/or myocarditis, which are chronic subclinical myopathies that are occasionally responsible for condemnation at slaughterhouses. Sarcocystis cruzi is a protozoan parasite of worldwide distribution transmitted by canids, most commonly associated with subclinical infection in cattle. Although S. cruzi infections can rarely lead to fatal systemic disease, fatal cardiac cases with confirmation of the etiologic diagnosis have not been reported, to our knowledge. We describe herein an unusual case of S. cruzi-induced fatal bovine eosinophilic myocarditis. A 22-mo-old, Holstein-Hereford heifer, in a group of 110 cattle on pasture, manifested growth retardation and died in February 2017. Autopsy revealed myriad yellow-green 1-3-mm coalescing foci, surrounded by fibrosis, affecting ~75% of the ventricular myocardium. Pulmonary edema, ascites, and hydrothorax were consistent with chronic congestive heart failure. Histology revealed severe eosinophilic, granulomatous, necrotizing myocarditis, with multinucleate giant cells, fibrosis, and mineralization. Numerous thin-walled protozoan cysts resembling Sarcocystis spp. were present in the necrotic foci and within the sarcoplasm of adjacent cardiomyocytes. PCR and sequencing of the 18S rRNA gene revealed 99.9-100% homology with S. cruzi. Sarcocystosis can be a rare cause of fatal myocarditis in cattle.

Leptospira interrogans serogroup Pomona serovar Kennewicki infection in two sheep flocks with acute leptospirosis in Uruguay.

Acute leptospirosis is an infrequent disease in sheep that can cause jaundice, haemolysis, haemoglobinuria, hepatitis and nephritis. In most reports the diagnoses have been made by clinical, pathological or serological evidence without isolation or direct identification of the agent. Here, we report one confirmed and one presumptive outbreak of acute leptospirosis in suckling lambs from two unrelated sheep farms in Uruguay with mortalities of 9/60 (15%) and 9/163 (5.5%) lambs. Both outbreaks occurred in Sep-Oct 2017 after heavy rainfall and flooding events. The main gross and histologic pathological findings in two autopsied lambs, one from each farm, included severe diffuse jaundice, haemoglobinuria, acute necrotizing hepatitis with cholestasis and interstitial nephritis. Leptospira interrogans serogroup Pomona serovar Kennewicki was isolated from sheep in both flocks and the same genotype was identified directly in clinical samples from infected animals, including one of the deceased lambs subjected to autopsy, by amplification and partial sequencing of rrs and secY genes. This serovar has recently been identified in infected cattle and humans in Uruguay. The impact of Leptospira spp. infection in ovine health, and the epidemiologic role of sheep as reservoirs of leptospirosis for humans and animals need further investigation.

Effect of gastrointestinal nematodes on serum copper and phosphorus of growing beef calves in northwestern Argentina.

The aim of this work was to study the effect of gastrointestinal nematodes (GINs) on copper (Cu) and phosphorus (P) in blood of beef cattle in two ranches (R1 and R2) located in northwestern Argentina. In 2015-2016 (R1) and 2016-2017 (R2), in each ranch, 22 weaned female calves were divided into two groups: calves treated systematically with 200 mcg/kg moxidectin every 45-50 days (TG) and untreated calves (UTG). The following parameters were measured: number of fecal eggs (epg), fecal cultures, serum Cu and P levels, and live weight gain (LWG). Differences between groups were compared using analysis of variance and Tukey test. GIN infections in both ranches were subclinical and moderate, showing the highest epg (R1 = 907 ± 754; R2 = 1049 ± 1040) by mid-winter. Epg values of TG groups were always negligible (> 93% of moxidectin efficacy). The dominant nematode genera were Cooperia and Haemonchus. The average serum Cu values (µg/dl) indicated low (R1 = 49.7 ± 18) and severe (R2 = 27.2 ± 14) deficiency. The effect of treatments was evident in both ranches from late winter, with TG showing significantly (p < 0.01) higher serum levels in winter, spring, and early autumn (R1 = 65.1, 50.9, and 60.3; R2 = 48.0, 25.7, and 22.4) than UTG (R1 = 44.3, 33.9, and 32.9; R2 = 25.5, 18.2, and 16.4). There were no differences in serum P levels between groups. LWG of TG increased significantly (p < 0.008) (27.2% in R1 and 38.6% in R2), with respect to those of UTG. This study showed a negative effect of GIN on serum Cu values in moderately infected growing calves.

Delayed type hypersensitivity induced by intradermal inoculation of a Neospora caninum tachyzoite antigen in previously exposed cattle.

The aim of this study was to evaluate delayed type hypersensitivity (DTH) induced by the intradermal inoculation of a Neospora caninum tachyzoite soluble lysate in cattle previously exposed with the protozoa. Four experimental groups were selected according to the prior exposure to N. caninum antigen. All cows were intradermally injected with a N. caninum tachyzoite soluble lysate and skinfold thickness growth at the inoculation sites was measured at 0, 24, 48, 72 and 96 h post inoculation (hpi). Additionally, specific antibodies and IFN-γ production were assessed. Cows experimentally infected with live N. caninum tachyzoites and cows naturally exposed to N. caninum developed skin reactions compatible with DTH between 24 and 96 hpi (p < 0.05). Moreover, cows inoculated with an experimental N. caninum vaccine and cows without evidence of exposure to N. caninum did not show a significant increase in skin thickness (p > 0.05). Furthermore, serological status of the animals was not modified due to the intradermal inoculation. The highest IFN-γ production was observed at 15 days after intradermal inoculation (p < 0.05). Therefore, these results suggest that cattle previously exposed to N. caninum develop a reaction compatible with DTH which could be useful as in vivo cell mediated immunity parameter for assessed bovine neosporosis.