Toxoplasma gondii infection in dairy ewes: Vertical transmission and influence on milk production and reproductive performance

A Retrospective Investigation of Abortion Storm in Abergele Goats, Waghimira Zone, Amhara Region, Ethiopia

A retrospective study was conducted in Abergele and Ziquala districts in Ethiopia to investigate the occurrence, impact, and potential risk factors for abortion in small ruminants linked to a regional abortion storm. Affected (case) and nonaffected (control) villages were compared to assess infectious and noninfectious risk factors causing abortions. A case village was defined as a village with abortion seen in all households enrolled in the study, while a control village is characterized by presence of abortion in two and fewer households. A questionnaire survey, focus group discussions, and serological examinations were used to assess the differences in the abortion rate between the case and control villages. The Rose Bengal Plate Test for Brucellosis, Toxoplasma gondii Antibody Test Kit for Toxoplasma gondii, and ELISA for Chlamydophila abortus and Coxiella burnetii were used to detect antibodies. Per village 15 household flocks were selected. In the case villages, all flocks were affected by abortion (a mean abortion of 13 animals in Abergele and 9 in Ziquala). In contrast, only three households reported abortions in the control villages. A total of 176 blood samples were collected from the case and control villages for further laboratory diagnosis of possible causes of abortion. Of the examined flocks, 17%, 10.2%, and 2.8% were positive for Coxiella burnetii, Toxoplasma gondii, and Chlamydophila abortus, respectively. However, antibodies against Brucella melitensis were not detected. While the seroprevalence was greater for some infectious agents of abortion, there was no significant difference between the case and control villages. It is clear that the abortion problem in the study villages is complex and likely due to a mix of poor husbandry practices and the presence of infectious diseases. To better understand the underlying causes of abortion, there is a need to conduct a longitudinal study involving testing for more pathogens at the household level combined with reliable data on husbandry practices.

High Toxoplasma gondii frequency of infection in the genital tract of ewes previously positive for the parasite DNA in meat, in Sidi Bouzid, Tunisia

The aim of the present study was to estimate the molecular prevalence of T. gondii along various segments of the genital tract of confirmed chronically infected ewes. Genital tracts were collected from 42 ewes; meat samples from the same ewes were previously confirmed positive for T. gondii DNA. The whole DNA was extracted from 4 parts of the genital tract (ovary, horns, body of the uterus and vagina). PCR was used to amplify a 114 base-pairs of T. gondii B1 gene. For all studied samples, 95.2 % had at least one infected genital part. Toxoplasma gondii infection was confirmed by sequencing 20 amplicons randomly chosen. The majority of infected animals has 4 T. gondii-infected genital anatomical parts. Principal component analysis (PCA) revealed a cluster of adult animals (>24 months) with positive PCR in the ovaries and the vagina and another cluster of Barbarine animals having positive PCR in the horns and body of the uterus. General linear model confirmed PCA results and showed a significant higher prevalence of T. gondii in the ovaries and vagina of older animals (p = 0.001 and p = 0.02, respectively) and a higher prevalence of T. gondii in the horns of the uterus of Barbarine animals (p = 0.03). Toxoplasma gondii seems to highly persist along the various segments of the ewe's genital tract but further investigations are necessary to link such prevalence with the pathological implications.

The presence of Toxoplasma gondii in soil, their transmission, and their influence on the small ruminants and human population: A review

The ecosystem approach has been developed since the 1940s. An ecosystem is a community of living organism and their interaction and conjugation with abiotic factors of the environment. The ecosystem is not endemic to the aquatic environment only but, the terrestrial environment is also considered to be a part of an ecosystem. Soil act as mother role for the survival of different microorganism. The Toxoplasma gondii oocysts stay survive for a long time in the soil. This presence of these oocysts might critically enhance the success of this parasite in two ways. First, this parasite can widespread; second, it can create a lot of consequences regarding animals and their economic value. Soil contamination caused by Toxoplasma gondii Y is a significant and profound issue for animals and public health. Therefore, the current study was aimed to summarize and correlate the soil and parasite, their transmission, infection, and some aspects related to T. gondii. The small animals are pose at a high risk therefore, it was concluded that some preventive measures should be taken to keep secure itself from zoonotic diseases.

Modeling the Ruminant Placenta-Pathogen Interactions in Apicomplexan Parasites: Current and Future Perspectives

Neospora caninum and Toxoplasma gondii are one of the main concerns of the livestock sector as they cause important economic losses in ruminants due to the reproductive failure. It is well-known that the interaction of these parasites with the placenta determines the course of infection, leading to fetal death or parasite transmission to the offspring. However, to advance the development of effective vaccines and treatments, there are still important gaps on knowledge on the placental host-parasite interactions that need to be addressed. Ruminant animal models are still an indispensable tool for providing a global view of the pathogenesis, lesions, and immune responses, but their utilization embraces important economic and ethics restrictions. Alternative in vitro systems based on caruncular and trophoblast cells, the key cellular components of placentomes, have emerged in the last years, but their use can only offer a partial view of the processes triggered after infection as they cannot mimic the complex placental architecture and neglect the activity of resident immune cells. These drawbacks could be solved using placental explants, broadly employed in human medicine, and able to preserve its cellular architecture and function. Despite the availability of such materials is constrained by their short shelf-life, the development of adequate cryopreservation protocols could expand their use for research purposes. Herein, we review and discuss existing (and potential) in vivo, in vitro, and ex vivo ruminant placental models that have proven useful to unravel the pathogenic mechanisms and the host immune responses responsible for fetal death (or protection) caused by neosporosis and toxoplasmosis.

Economic and public health importance of Toxoplasma gondii infections in sheep: 2009-2020

Toxoplasma gondii infections are common in humans and animals worldwide. The present review summarizes worldwide information on the prevalence of clinical and subclinical infections, epidemiology, diagnosis, control, and genetic diversity of T. gondii in sheep in the past decade. There is debate and uncertainty concerning repeat congenital infection as evidenced by finding T. gondii DNA in progeny of chronically infected sheep. However, there is no concrete evidence that T. gondii is the cause of repeated abortions in sheep. Recent data concerning pathogenesis of abortion in acutely infected sheep are reviewed. PCR-RFLP typing of T. gondii DNA derived from viable T. gondii isolates or tissues of infected sheep revealed low genetic diversity in sheep in Europe, Africa, Asia and North America but high diversity in South America. This review will be of interest to biologists, parasitologists, veterinarians, and public health workers.

Toxoplasma gondii infection and toxoplasmosis in farm animals: Risk factors and economic impact

The protozoan parasite Toxoplasma gondii is a zoonotic parasite that can be transmitted from animals to humans. Felids, including domestic cats, are definitive hosts that can shed oocysts with their feces. In addition to infections that occur by accidental oral uptake of food or water contaminated with oocysts, it is assumed that a large proportion of affected humans may have become infected by consuming meat or other animal products that contained infective parasitic stages of T. gondii. Since farm animals represent a direct source of infection for humans, but also a possible reservoir for the parasite, it is important to control T. gondii infections in livestock. Moreover, T. gondii may also be pathogenic to livestock where it could be responsible for considerable economic losses in some regions and particular farming systems, e.g. in areas where the small ruminant industry is relevant. This review aims to summarize actual knowledge on the prevalence and effects of infections with T. gondii in the most important livestock species and on the effects of toxoplasmosis on livestock. It also provides an overview on potential risk factors favoring infections of livestock with T. gondii. Knowledge on potential risk factors is prerequisite to implement effective biosecurity measures on farms to prevent T. gondii infections. Risk factors identified by many studies are cat-related, but also those associated with a potential contamination of fodder or water, and with access to a potentially contaminated environment. Published information on the costs T. gondii infections cause in livestock production, is scarce. The most recent peer reviewed reports from Great Britain and Uruguay suggest annual cost of about 5-15 million US $ per country. Since these estimates are outdated, future studies are needed to estimate the present costs due to toxoplasmosis in livestock. Further, the fact that T. gondii infections in livestock may affect human health needs to be considered and the respective costs should also be estimated, but this is beyond the scope of this article.

Large-Scale Epidemiological Study on Toxoplasma gondii Seroprevalence and Risk Factors in Sheep in Estonia: Age, Farm Location, and Breed Associated with Seropositivity

Toxoplasma gondii is a zoonotic parasite of major veterinary and public health importance. The parasite is common in many host species in Estonia, however, information about the seroprevalence in the local sheep population is lacking. We estimated T. gondii seroprevalence and evaluated a limited selection of possible risk factors for T. gondii seropositivity in sheep raised in Estonia. Sera from 1599 sheep from 122 flocks, collected during 2012-2013, were diluted to 1:40 and screened for the presence of anti-T. gondii immunoglobulin G antibodies using a commercial direct agglutination test. The cutoff titer for seropositivity was 40. A total of 667 of the 1599 sheep were T. gondii seropositive, yielding an apparent seroprevalence estimate of 41.71% (95% confidence interval 39.31-44.14). At least one seropositive sheep was detected on the majority (88.53%) of the farms. T. gondii seroprevalence was significantly lower in lambs (age <12 months) than in adults (age ≥12 months) (11.11% and 42.16%, respectively). The seroprevalence increased steeply with age in the first years of life. A multivariable random-effects logistic regression model identified being an adult (odds ratio [OR] 9.55) and being from a farm located on the islands (OR 2.51) as risk factors for T. gondii seropositivity, while being of Texel breed appeared as a protective factor (OR 0.34) when compared with the Estonian Blackhead breed. Exposure to T. gondii was widespread among the investigated sheep. Undercooked meat and unpasteurized milk from sheep from Estonia should be considered possible sources of T. gondii infections to other hosts, including humans.