A survey on Apicomplexa protozoa in sheep slaughtered for human consumption

Red foxes (Vulpes vulpes) and raccoon dogs (Nyctereutes procyonoides) as potential spreaders of Sarcocystis species

Background

Sarcocystis includes a global group of apicomplexan parasites with two-host life cycle frequently circulating in wildlife and domestic hosts, including humans. Two of the most important wild terrestrial carnivores acting as definitive hosts are the red fox and raccoon dog, due to their wide distribution in Europe and usage of wild and farmed animals as prey. This study was conducted to determine the prevalence of Sarcocystis in hunted red foxes and raccoon dogs from nine regions of the Czech Republic and to identify isolated sporocysts by molecular techniques.

Methods

Approximately 5 g of the contents of large intestine from 200 animals (197 red foxes and three raccoon dogs) were examined by flotation centrifugation coprological method. Only samples of 50 red foxes and one raccoon dog positive to Sarcocystis spp. were used for the nested PCR (nPCR) method to amplify a fragment or partial sequence on the cox1 gene. Ten species-specific primer pairs for detection of Sarcocystis spp. using farm animals as intermediate hosts were utilized.

Results

In total, 38.1% of the red foxes and 66.7% of the raccoon dogs were positive to Sarcocystis by light microscopy. The molecular characterization resulted in the identification of five species in the red fox: S. arieticanis, S. capracanis, S. cruzi, S. miescheriana, and S. tenella, while the PCR was negative for the sole raccoon dog. The highest intraspecific variation was found for S. miescheriana, while S. tenella was the most prevalent. Co-infections occurred in the large intestine of the red fox. No zoonotic species were found in our samples.

Conclusion

This is the first study where the potential role of the red fox and raccoon dogs as spreaders of Sarcocystis to farm animals in the Czech Republic is shown. The use of species-specific primers provides a fast and easy method for screening multiple samples for a particular Sarcocystis species.

The Distribution of Sarcocsytis Species Described by Ungulates-Canids Life Cycle in Intestines of Small Predators of the Family Mustelidae

PURPOSE

Using molecular techniques, we have previously shown that carnivorous mammals of the family Mustelidae might be common definitive hosts for various protozoan Sarcocystis species. In the present study we aimed to unravel whether Sarcocystis species using ungulates as intermediate hosts and canids or felids as definitive hosts can be found in intestine of mustelids.

METHODS

Small intestine samples of 93 individual mustelids of five different species from Lithuania were examined. Sarcocystis species were identified based on species-specific PCR and subsequent cox1 sequencing.

RESULTS

Six Sarcocystis species (S. arieticanis, S. bertrami, S. capracanis, S. capreolicanis, S. linearis and S. morae) defined by ungulate-canid life cycle were detected for the first time in small intestines of mustelids. By contrast, the prevalence of Sarcocystis characterised by ungulate-felid life cycle was low (3.2%). Overall, 76% of the examined animals were positive for at least one of the studied Sarcocystis species. Four species, S. arieticanis, S. bertrami, S. capracanis and S. morae were most commonly found, with the detection rate of about 40%.

CONCLUSIONS

The current finding, in addition to our previous studies, suggests that mustelids play an important role in the spread of various Sarcocystis species.

Seroepidemiological and biomolecular survey on Toxoplasma gondii in Sardinian wild boar (Sus scrofa)

Toxoplasma gondii is a zoonotic parasite able of infecting all warm-blooded animals. Toxoplasmosis is one of the major foodborne diseases globally. The consumption of wild boar (Sus scrofa) meat from recreational hunting has been linked to outbreaks of human toxoplasmosis. The island of Sardinia (Italy) contains a large wild boar population, thus providing an opportunity to assess the distribution of Toxoplasma in this species and the associated risks of transmission to humans. A total of 562 wild boars were screened: heart and meat juice samples were tested for T. gondii DNA via nested-PCR and IgG anti-Toxoplasma by commercial ELISA. Anti-Toxoplasma IgG were detected in 24.6% (138/562) of animals, while 37.2% (209/562) of the heart samples were PCR positive. The prevalence of T. gondii antibodies and DNA highlights the potential role of wild boar as an important reservoir for this parasite. The study suggests that wild boar could play a significant role in spreading the parasite to humans. As wild boar numbers are increasing throughout their range, their potential role in transmitting toxoplasmosis should be communicated to stakeholders, and the impact of different population control methods on disease transmission should be thoroughly assessed to mitigate potential threats effectively.

Purification and characterization of cysteine protease of Sarcocystis fusiformis from infected Egyptian water buffaloes

Sarcocystis spp. infects water buffaloes (Bubalus bubalis) causing sarcocystosis. In the present study, Sarcocystis fusiformis was recognized in Egyptian water buffaloes based on histological observation and molecular analysis of internal transcribed spacer 1 (ITS1), 18S ribosomal RNA (18S rRNA) and cytochrome c oxidase subunit I (COX-1) gene fragments. Chemotherapy and vaccines against Sarcocystis spp. could potentially target proteases because they may play a crucial role in the infection. Cysteine proteases are multifunctional enzymes involved in vital metabolic processes. However, the involvement of proteases in S. fusiform infection has not yet been characterized. Here, the purification and study on some biochemical properties of protease isolated from cysts of S. fusiform were carried out. Protease with a molecular weight of 100 kDa was purified. LC-MS/MS analyzed the protein sequence of purified protease and the data suggested that the enzyme might be related to the cysteine protease. The purified protease exhibited maximum activity at pH 6 and a temperature of 50 °C. The Michaelis-Menten constant (Km), the maximum velocity (Vmax), and the turnover number (Kcat) were determined. The complete inhibition effect of cysteine inhibitors indicated that the purified enzyme is a cysteine protease. The results suggested that S. fusiform proteolytic enzyme may be necessary for parasite survival in water buffaloes by digesting host tissues. Therefore, cysteine protease could be a suitable target for vaccinations.

A Systematic Meta-Analysis of Global Sarcocystis Infection in Sheep and Goats

Sarcocystosis is an intracellular parasitic disease caused by Sarcocystis spp. that has a worldwide prevalence. Symptoms of the disease include diarrhea and muscle pain. The disease poses a threat to the health of animals. The aim of this review is to investigate the global prevalence of Sarcocystis infection in sheep and goats during 2013-2022. We searched five databases: Web of Science, Science Direct, PubMed, Scopus, and Google Scholar. A total of 36 articles containing 44 datasets met the criteria and were included in the study. The total infection rates of Sarcocystis in sheep and goats were 66.3% (95% CI, 51.79-79.38%) and 52.1% (95% CI, 29.45-74.23%), respectively. It was found that Sarcocystis species tend to have a host species preference. Coinfection of S. tenella and S. arieticanis often occurred in sheep, and goats were frequently infected with S. capracanis. Age and sex were identified as risk factors for Sarcocystis infection in sheep and goats. The infection rates of female and male animals were significantly different, with females having a higher infection rate. Age-adjusted analysis showed that infection rates in animals older than one year were higher than in animals younger than one year. This study unveiled the global distribution of Sarcocystis and sheds light on its transmission in sheep and goats.

Molecular Detection of Toxoplasma gondii in Blood Samples of Domestic Livestock in the Republic of Korea

Toxoplasma gondii, a major zoonotic pathogen distributed worldwide, causes severe infections in humans, animals, and birds. However, limited information is available regarding T. gondii infection in livestock in the Republic of Korea (ROK). Herein, we determined the prevalence of T. gondii infection in livestock in the ROK and identified animal species that can potentially transmit T. gondii to humans. B1 gene-targeting nested polymerase chain reaction detected T. gondii DNA in 3.3% (2/61), 2.9% (3/105), 14.1% (11/78), and 15.4% (14/91) of dairy cattle, beef cattle, Boer goats, and Korean native goats, respectively. The prevalence of T. gondii was significantly higher (p = 0.002) in goats than in cattle. The risk of contracting T. gondii infection was significantly higher by 6.18-fold in Korean native goats (95% confidence interval [CI]: 1.72–22.27%, p = 0.005) and by 5.58-fold in Boer goats (95% CI: 1.50–20.76%, p = 0.010) than in beef cattle. Our T. gondii DNA sequences exhibited 97.1–100% homology with those obtained from various hosts in other countries. To the best of our knowledge, this is the first study to report T. gondii infection using the blood samples of domestic ruminants in the ROK. The results revealed that the prevalence of T. gondii infection is higher in goats than in cattle as determined by molecular detection. Thus, these findings suggest that T. gondii can be transmitted from ruminants to humans via meat consumption.

DGPD: a knowledge database of dense granule proteins of the Apicomplexa

Apicomplexan parasites cause severe diseases in human and livestock. Dense granule proteins (GRAs), specific to the Apicomplexa, participate in the maintenance of intracellular parasitism of host cells. GRAs have better immunogenicity and they can be emerged as important players in vaccine development. Although studies on GRAs have increased gradually in recent years, due to incompleteness and complexity of data collection, biologists have difficulty in the comprehensive utilization of information. Thus, there is a desperate need of user-friendly resource to integrate with existing GRAs. In this paper, we developed the Dense Granule Protein Database (DGPD), the first knowledge database dedicated to the integration and analysis of typical GRAs properties. The current version of DGPD includes annotated GRAs metadata of 245 samples derived from multiple web repositories and literature mining, involving five species that cause common diseases (Plasmodium falciparum, Toxoplasma gondii, Hammondia hammondi, Neospora caninum and Cystoisospora suis). We explored the baseline characteristics of GRAs and found that the number of introns and transmembrane domains in GRAs are markedly different from those of non-GRAs. Furthermore, we utilized the data in DGPD to explore the prediction algorithms for GRAs. We hope DGPD will be a good database for researchers to study GRAs.

Database URL: http://dgpd.tlds.cc/DGPD/index/

Ovine Neosporosis: The Current Global Situation

Simple Summary

This review summarizes the current global situation of Neospora caninum infection in sheep by referring to all of the available descriptions of natural ovine neosporosis to date, focusing on epidemiology, clinical signs, lesions, and diagnosis. The data suggest that ovine neosporosis is more prevalent than currently thought, that it has increased in the last few decades, and that it should now be considered in the differential diagnosis when investigating abortion in sheep.

Abstract

In the past 20 years, Neospora caninum infection in sheep has been reported in at least 31 countries worldwide from all sheep-rearing continents (Europe, Asia, the Americas, Africa, and Oceania), and its role as an abortifacient agent is becoming more evident. Most studies of ovine neosporosis have focused on its epidemiology, based primarily on serological analysis, with only a few studies investigating the actual presence of the parasite by PCR and/or IHC. Individual seroprevalence rates were highly variable between countries, and even between regions within the same country, ranging from 0.0% to 67.4% positive. Furthermore, most of the studies were not directly comparable due to differences in experimental designs, sample sizes, husbandry systems, ecological factors, and serological tests (e.g., IFAT, ELISA, MAT, Western blot). The latter, along with the scarcity of studies on the relevance of N. caninum as an abortifacient agent, may bias the perception of the importance of this disease. This review summarizes the situation of N. caninum infection in sheep using all available published studies describing natural ovine neosporosis. The epidemiology shows that ovine neosporosis is found worldwide, and it poses a relevant risk to the sustainability of sheep flocks.

Molecular Identification of Sarcocystis Species in Sheep from Lithuania

Data on the distribution of different Sarcocystis species in various muscles of sheep are scarce. In the present study, 190 diaphragm, oesophagus, and heart muscle samples of 69 sheep raised in Lithuania were examined for the presence of Sarcocystis spp. Under a light microscope, two morphological types of microcysts corresponding to S. arieticanis and S. tenella were detected. Eight and 12 sarcocysts of S. arieticanis and S. tenella, respectively, were isolated and characterised by the sequencing of a portion of cox1. The sequence comparisons revealed the highest similarity between European and Asian isolates of S. arieticanis and S. tenella obtained from domestic sheep and other wild Caprinae hosts. Based on peptic digestion, nested PCR targeting cox1, and sequencing, a 100% infection prevalence of S. arieticanis and S. tenella was observed in the 69 studied animals. The occurrence of S. tenella was significantly higher in the diaphragm than in the oesophagus (χ2 = 13.14, p < 0.001), whereas differences in the prevalence of S. arieticanis in the studied muscle types were insignificant (χ2 = 1.28, p > 0.05). Further molecularly based epidemiological studies are needed to compare the prevalence of Sarcocystis species in various muscles of sheep raised in different geographic regions.