Evaluation of Western blot, ELISA and latex agglutination tests to detect Toxoplasma gondii serum antibodies in farmed red deer

Epidemiologic and Public Health Significance of Toxoplasma gondii Infections in Venison: 2009-2020

Toxoplasma gondii infections are common in humans and animals worldwide. The ingestion of food or water contaminated with oocysts excreted by infected cats or ingestion of uncooked or undercooked meat containing tissue cysts of T. gondii are the 2 major modes of transmission of T. gondii. Deer are a popular game. Recently, outbreaks of clinical toxoplasmosis were reported in humans in North America linked to ingestion of undercooked venison. Here, we review prevalence, persistence of infection, clinical disease, epidemiology, and public health risks of T. gondii infections in deer and other cervids for the past decade. Estimates of worldwide serological prevalence are summarized individually for each species of deer, elk, moose, and caribou. Genetic diversity of 112 viable isolates of T. gondii from cervids is discussed, including its public health significance. Prevalence of T. gondii in deer is very high. Any part of a deer, including liver, spleen, and muscles, should be cooked thoroughly before human consumption.

Investigation of Toxoplasma gondii and association with early pregnancy and abortion rates in New Zealand farmed red deer (Cervus elaphus)

This study tested for association between Toxoplasma gondii and pregnancy and abortion to investigate sub-optimal reproduction in farmed red deer (Cervus elaphus). Sera from a sub-sample (n = 2304) of pregnant and non-pregnant hinds in early gestation at first pregnancy scan (scan 1) and approximately at the end of second trimester at second pregnancy scan (scan 2) were tested for T. gondii antibodies using a validated ELISA. Foetuses and/or uteri from pregnant, non-pregnant, and aborting hinds at scan 1, scan 2, or weaning were tested for T. gondii DNA by nested PCR. At scan 1, 31.1% of 861 rising two-year-old (R2) and 28.3% of 357 mixed-aged (MA, ≥ 2 years) hinds were sero-positive. There was no association between scan 1 serology and non-pregnancy at animal (R2, p = 0.05 and MA, p = 0.43) or herd level (R2, p = 0.37). Toxoplasma gondii DNA was detected in 3/18 placenta and 4/18 foetal brains from aborting R2 hinds and 15/157 R2 and 3/21 MA uteri from non-pregnant hinds at scan 1. At scan 2, sero-prevalence was higher (odds ratio = 1.6, 95% CI = 1.04-2.48) in aborted (34.3% of 268) than in non-aborted (23.5% of 446) R2 hinds (p = 0.03) and 7.9% of abortions between scans were attributable to T. gondii exposure. Within-herd sero-prevalence at scan 2 was positively associated with daily abortion rate in R2 herds with aborted hinds (p < 0.001) but not in MA herds (p = 0.07). Toxoplasma gondii DNA was detected in 27/169 uteri, 2/20 cotyledons, and 1/5 foetal brains from aborted hinds at scan 2 and in uteri from 5/33 hinds not rearing a calf to weaning. Toxoplasma gondii RFLP genotyping of five loci revealed a unique type I/III genotype pattern, TgRDNZ1, in a foetal brain sample, not been previously reported in deer. These findings provide serological and molecular evidence that T. gondii infection is associated with abortion in red deer, possibly in all three trimesters.

Seroprevalence of Toxoplasma gondii in wild sika deer in Japan

Toxoplasmosis is a food-borne infection that is widespread around the world, causing congenital disorders and opportunistic infections. Ingestion of undercooked meat is one of the risk factors for infection with the causative agent, Toxoplasma gondii. Japanese people occasionally eat rare meat as a traditional cuisine style called "Sashimi". A rapid increase in venison consumption in Japan has occurred mainly due to enhanced population control of wild Japanese deer (Cervus nippon) in recent decades. In particular, Yezo-sika deer (C. n. yesoensis) in Hokkaido (the northernmost and largest prefecture in Japan) is frequently supplied to markets as branded game/bushmeat. To study the possible burden of Toxoplasma gondii among wild Yezo-sika deer, plasma samples of Yezo-sika deer hunted during two seasons, 2010-2012, in Eastern Hokkaido were investigated. A total 80 samples were examined using the Sabin-Feldman dye test, which is highly specific and sensitive for identifying the development and persistence of antibodies after primary Toxoplasma infection, demonstrating that 38 cases (47.5%) were seropositive (cut-off titer <1:16). Antibody prevalence of T. gondii in female deer was higher than in males. Adult deer aged 3 years or over showed higher seroprevalence compared with younger animals. The overall seroprevalence fluctuated significantly according to the season when the deer were hunted. These results indicated widespread infection of T. gondii among Japanese wild Yezo-sika deer, suggesting that both appropriate handling and treatment of bushmeat are required to prevent food-borne toxoplasmosis in Japan.

New prevalence surveillance of Toxoplasma gondii among rodents and stray cats by ELISA avidity and nested PCR methods, Northeast of Iran

Rodents and stray cats are the sources of many parasitic infections including T. gondii, for other animals and human. Toxoplasmosis has a wide range of laboratory factors in its intermediate and definite hosts. Regarding the importance of rodents and stray cats as the hosts that spread the Toxoplasma gondii, it is necessary to obtain comprehensive information about these animals in the life cycle of T. gondii. The objective was to investigate the new prevalence of toxoplasmosis among target animals in Iran, using GRA6 gene in combinacion with ELISA avidity. In this study, 286 rodents and 210 stray cats were collected and their heart tissues extracted to obtain DNA, blood samples and IgG Ab of T.gondii parasite. We detected the positive tissue samples in our study by the nested-PCR method. Then, we examined T. gondii IgG ELISA avidity for assessment of toxoplasmosis among rodents and stray cats. This study, was conducted in January to March 2017, based on the prevalence study. The findings revealed that 246/286 (86.01%) of rodents and 180/210 (85.71%) of stray cats were positive by IgG ELISA avidity methods. moreover, 68 rodents samples and 38 stray cats samples were positive concerning the GRA6 Toxoplasma gene; and these positive samples were at intermediate levels for IgG avidity. We concluded that the new prevalence of toxoplasmosis among rodents and stray cats was at high levels, using the serologic method in Northeast of Iran and the results of quantitative ELISA avidity were as the same as those of the nested-PCR for detecting recent toxoplasmosis in these hosts.