Detection of toxoplasma antibodies in sera of Salmonidae by ELISA

Toxoplasma gondii in Foods: Prevalence, Control, and Safety

Toxoplasma gondii is an obligate intracellular parasite that causes toxoplasmosis, with approximately one third of the population around the world seropositive. The consumption of contaminated food is the main source of infection. These include meat products with T. gondii tissue cysts, and dairy products with tachyzoites. Recently, contamination has been detected in fresh products with oocysts and marine products. Despite the great health problems that are caused by T. gondii, currently there are no standardized methods for its detection in the food industry. In this review, we analyze the current detection methods, the prevalence of T. gondii in different food products, and the control measures. The main detection methods are bioassays, cell culture, molecular and microscopic techniques, and serological methods, but some of these do not have applicability in the food industry. As a result, emerging techniques are being developed that are aimed at the detection of multiple parasites simultaneously that would make their application more efficient in the industry. Since the prevalence of this parasite is high in many products (meat and milk, marine products, and vegetables), it is necessary to standardize detection methods, as well as implement control measures.

Toxoplasma gondii in mollusks and cold-blooded animals: a systematic review

Toxoplasma gondii (T. gondii) is known for its ability to infect warm-blooded vertebrates. Although T. gondii does not appear to parasitize cold-blooded animals, the occurrence of T. gondii infection in marine mammals raises concerns that cold-blooded animals (frogs, toad, turtles, crocodiles, snakes, and fish) and shellfish are potential sources of T. gondii. Therefore, this systematic review aimed to determine the prevalence of T. gondii in mollusks and cold-blooded animals worldwide. We searched PubMed, ScienceDirect, ProQuest, Scopus, and Web of Science from inception to 1 August 2020 for eligible papers in the English language and identified 26 articles that reported the prevalence of T. gondii in mollusks and cold-blooded animals. These articles were subsequently reviewed and data extracted using a standard form. In total, 26 studies [involving 9 cross-sectional studies including 2988 samples of cold-blooded animals (129 positive cases for T. gondii) and 18 cross-sectional studies entailing 13 447 samples of shellfish (692 positive cases for T. gondii)] were included in this study. Although this study showed that shellfish and cold-blooded animals could be potential sources of T. gondii for humans and other hosts that feed on them, further investigations are recommended to determine the prevalence of T. gondii in shellfish and cold-blooded animals.

Potential Risk of Three Zoonotic Protozoa (Cryptosporidium spp., Giardia duodenalis, and Toxoplasma gondii) Transmission from Fish Consumption

In recent decades, worldwide fish consumption has increased notably worldwide. Despite the health benefits of fish consumption, it also can suppose a risk because of fishborne diseases, including parasitic infections. Global changes are leading to the emergence of parasites in new locations and to the appearance of new sources of transmission. That is the case of the zoonotic protozoa Cryptosporidium spp., Giardia duodenalis, and Toxoplasma gondii; all of them reach aquatic environments and have been found in shellfish. Similarly, these protozoa can be present in other aquatic animals, such as fish. The present review gives an overview on these three zoonotic protozoa in order to understand their potential presence in fish and to comprehensively revise all the evidences of fish as a new potential source of Cryptosporidium spp., Giardia duodenalis, and Toxoplasma gondii transmission. All of them have been found in both marine and freshwater fishes. Until now, it has not been possible to demonstrate that fish are natural hosts for these protozoa; otherwise, they would merely act as mechanical transporters. Nevertheless, even if fish only accumulate and transport these protozoa, they could be a "new" source of infection for people.

Seroepidemiology of Toxoplasma gondii infection in elderly people in a northern Mexican city

Whereas it is well-known that the seroprevalence of infection with Toxoplasma gondii increases with age, details of the seroepidemiology of infection in elderly people are largely unknown. Anti-T. gondii IgG and IgM antibody levels were determined in 483 subjects aged ≥60 years old in Durango City, Mexico, using enzyme-linked immunosorbent assays. Socio-demographic, clinical, and behavioral characteristics from each participant were also obtained. In total, 58 (12%) of 483 participants (mean age 70.35±6.63 years) had anti-T. gondii IgG antibodies, and 14 (2.9%) also had anti-T. gondii IgM antibodies. Seroprevalence of infection varied significantly with age, birthplace, and educational level. Seroprevalence increased with age, especially in women (p=0.01), and was higher in subjects born outside of Durango State than those born within Durango State (p=0.008). Seroprevalence was higher in men with up to 12 years of education than in men with more than 12 years of education (p=0.01). Multivariate analysis of behavioral data showed a positive association of T. gondii infection with the presence of cats in the neighborhood, as well as consumption of boar, pigeon, iguana, and armadillo meats, and chorizo. Gender-specific analysis showed the described associations in women but not in men. In contrast, consumption of beef showed a negative association with T. gondii infection. This is the first report of the seroprevalence and contributing factors for T. gondii infection in elderly people, and of an association of the consumption of armadillo and iguana meats with T. gondii infection. Our results will provide the basis for the design of optimal preventive measures against T. gondii infection.