Foodborne outbreaks of human toxoplasmosis

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.

Sulfadiazine analogs: anti-Toxoplasma in vitro study of sulfonamide triazoles

Toxoplasmosis is an infection that prevails all over the world and is caused by the obligate intracellular protozoan parasite Toxoplasma gondii (T. gondii). Promising novel compounds for the treatment of T. gondii are introduced in the current investigation. In order to test their in vitro potency against T. gondii tachyzoites, six 1,2,3-triazoles-based sulfonamide scaffolds with terminal NH2 or OH group were prepared and investigated as sulfadiazine equivalents. When compared to sulfadiazine, which served as a positive control, hybrid molecules showed much more anti-Toxoplasma activity. The results showed that the IC50 of the examined compounds 3(a-f) were recoded as 0.07492 μM, 0.07455 μM, 0.0392 μM, 0.03124 μM, 0.0533 μM, and 0.01835 μM, respectively, while the sulfadiazine exhibited 0.1852 μM. The studied 1,2,3-triazole-sulfadrug molecular conjugates 3(a-f) revealed selectivity index of 10.4, 8.9, 25.4, 21, 8.3, and 29; respectively. The current study focused on the newly synthesized amino derivatives 3(d-f), as they contain the more potent amino groups which are recognized to be essential elements and promote better biological activity. Extracellular tachyzoites underwent striking morphological alterations after 2 h of treatment as seen by scanning electron microscopy (SEM). Additionally, the intracellular tachyzoite exposed to the newly synthesized amino derivatives 3(d-f) for a 24-h period of treatment revealed damaged and altered morphology by transmission electron microscopic (TEM) indicating cytopathic effects. Moreover, compound 3f underwent the most pronounced changes, indicating that it had the strongest activity against T. gondii.

Global prevalence and genotype distribution of Microsporidia spp. in various consumables: a systematic review and meta-analysis

Water and food sources play a major role in the distribution and transfer of microsporidia infection to animals and humans. So, this systematic review and meta-analysis aimed to assess the status and genetic diversity of microsporidia infection in water, vegetables, fruits, milk, cheese, and meat. The standard protocol of Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines was followed. Scopus, PubMed, Web of Science, and Google Scholar were searched from 1 January 2000 and 1 February 2023. The point estimates and 95% confidence intervals (CIs) were calculated using a random-effects model. Of the 1,308 retrieved studies, 35 articles were included in the final meta-analysis. The pooled prevalence of microsporidia infection in mixed water, mixed fruits, mixed vegetables, and milk was 43.3% (95% CI, 33-54.2%; I², 94.86%), 35.8% (95% CI, 5.3-84.8%; I², 0), 12% (95% CI, 4.9-26.6%; I², 96.43%), and 5.8% (95% CI, 2.7-12%; I², 83.72%), respectively. Considering the genotypes, microsporidia with genotype D in water sources and genotype CD6 in vegetables/fruits were the highest reported genotypes. Given the relatively high prevalence of microsporidiosis (especially in water sources), designing strategies for control, and prevention of microsporidia infection in these sources should be recommended.

Knowledge and practices on consumption of free-range chickens in selected rural communities of KwaZulu-Natal, South Africa, with focus on zoonotic transmission of Toxoplasma gondii and Toxocara spp

Chickens are a host to a variety of pathogens of zoonotic importance and this depends more on the husbandry system practiced. Toxoplasma gondii and Toxocara spp which are more prevalent in free-range chickens (FRC) can be acquired by humans via the ingestion of raw or undercooked meat (muscle) and/or viscera contaminated with infective stages of T. gondii and Toxocara spp. This study aimed to assess knowledge and practices on the household consumption of FRC meat and viscera by rural communities in KwaZulu-Natal (KZN) province, South Africa, as a risk factor in the transmission of zoonotic pathogens with special emphasis on T. gondii and Toxocara spp. A cross-sectional study was conducted on twenty (20) randomly selected households in four selected communities located on the northern coast (Gingindlovu and Ozwathini) and southern coast (uMzinto and Shongweni) of KZN province using a semi-structured questionnaire. To determine the presence of selected zoonotic pathogens in FRC, birds were purchased from randomly selected households in the study localities for sacrifice. Brain tissues were collected and subjected to molecular detection of T. gondii using TOX4 and TOX5 primers while other tissues and organs that were collected were subjected to molecular detection of Toxocara spp using Nem 18S primers. Questionnaire data were analyzed using the statistical package for social sciences (SPSS) version 25.0. Descriptive and chi-square statistics were used to assess knowledge and practices related to FRC consumption and zoonosis transmission. Molecular results showed four positive samples for T. canis from Gingindlovu (n = 1), uMzinto (n = 1), and Shongweni (n = 2). The role of FRC consumption in zoonosis transmission is discussed.

Primary ocular toxoplasmosis secondary to venison consumption

Purpose

To describe primary ocular toxoplasmosis infection related to ingestion of undercooked venison.

Observations

This single site, retrospective case series reviewed 4 patients with primary ocular toxoplasmosis that was acquired by ingesting undercooked venison. De-identified data was collected regarding baseline patient characteristics including age, sex, past medical and ocular history, onset of symptoms, visual acuity (VA), response to treatment, and workup. All patients with acquired toxoplasmosis had similar chronology of systemic and ocular symptoms. Exposure occurred in October or November and systemic symptoms developed within 2 weeks, followed by ocular symptoms an average of 2.6 months later. Average age at onset was 56 ± 13 (age ± SD) years old and all were male. Average initial and final VA were 20/50 and 20/50, respectively. Positive anti-toxoplasma IgM and IgG serologies were found in all cases. All patients were treated with trimethoprim/sulfamethoxazole and achieved rapid improvement. Complications occurred in 50% of cases and included epiretinal membrane, cystoid macular edema, vitreoretinal traction, and neovascularization.

Conclusions and importance

Consumption of undercooked venison is a source of primary ocular toxoplasmosis even in immunocompetent hosts and has a clear chronology. A presentation of retinochoroiditis during the winter months should prompt questioning for exposure to wild game.

Toxoplasmosis in Human and Animals Around the World. Diagnosis and Perspectives in the One Health Approach

Toxoplasmosis is a unique health disease that significantly affects the health of humans, domestic animals, wildlife and is present in ecosystems, including water, soil and food. Toxoplasma gondii is one of the best-adapted parasites in the word. This parasite is able to persist for long periods in its hosts, in different geographic regions of the word. This review summarizes the current literature of these themes, focusing on: (1) toxoplasmosis, a zoonotic infection; (2) One health approach and toxoplasmosis; (3) human toxoplasmosis; (4) animal toxoplasmosis; (5) toxoplasmosis diagnosis, as immunological, parasitological and molecular diagnosis; (6) T. gondii outbreaks caused by infected meat, milk and dairy products, as well as, vegetables and water consume; (7) studies in experimental models; (8) genetic characterization of T. gondii strains; (9) extracellular vesicles and miRNA; and (10) future perspectives on T. gondii and toxoplasmosis. The vast prevalence of toxoplasmosis in both humans and animals and the dispersion and resistence of T. gondii parasites in environment highlight the importance of the one health approach in diagnostic and control of the disease. Here the different aspects of the one health approach are presented and discussed.

Human and environmental factors driving Toxoplasma gondii prevalence in wild boar (Sus scrofa)

As one of the most relevant foodborne diseases, it is essential to know the factors related to the transmission, persistence and prevalence of Toxoplasma gondii infection. Eurasian wild boar (Sus scrofa) might play a relevant role in T.gondii's life cycle. This species is the most consumed big game animal in Spain and may act as a source of infection if the meat is eaten raw or undercooked or due to cross-contaminations. Additionally, wild boar can act as an excellent bioindicator of T.gondii circulation in the ecosystem, because its natural behaviour leads to exposure to oocysts from the soil when rooting and tissular bradyzoites when scavenging. A total of 1003 wild boar were sampled from 2010 to 2017 in Mediterranean Spain. Blood samples were tested with an indirect ELISA test giving a total of 14.1% (95% confidence interval 12.0-16.4%) positive results. The prevalence was not homogeneous in neither the animals nor the sampled districts. Significant differences were found regarding age, climatic conditions and human space occupancy. Human population aggregation, assessed by Demangeon's index, was identified as an influential factor in T.gondii infection risk. This multiple approach allows us to evaluate local risks for human and environmental contamination.

Comparison of Direct and Indirect Toxoplasma gondii Detection and Genotyping in Game: Relationship and Challenges

The importance of game as a source of Toxoplasma gondii (T. gondii) infection in humans is largely unknown. New data on the presence of T. gondii in game hunted in the Federal State of Brandenburg, Germany, were obtained by direct and indirect detection (ELISA). DNA extracted either directly (5 g heart or foreleg muscle, DE) or after acid pepsin digestion (50 g heart, PD) or enriched by magnetic capture (50 g heart, MC) was examined by real-time PCR (qPCR). ELISA revealed seroprevalences of 20% in wild boar (Sus scrofa), 11% in roe deer (Capreolus capreolus) and 6% in red deer (Cervus elaphus). T. gondii DNA was detected by at least one direct detection method in 12% of wild boar, 6% of roe deer, 2% of fallow deer (Dama dama) and 2% of red deer. In both, positive wild boar and roe deer, T. gondii type II specific alleles were the most prevalent, as assessed by PCR-restriction fragment length polymorphism. The highest proportion of positive animals was detected by MC qPCR, followed by PD qPCR with a similar proportion of positive findings. Investigation of 50 g of heart muscle revealed a significantly higher proportion of positive qPCR results than analysis of 5 g (p = 0.048). An association between seropositivity and direct detection was evident in wild boar and roe deer (p < 0.001). Infectivity of T. gondii DNA–positive samples was confirmed by bioassay (4/4), providing evidence that game could represent a relevant source of viable T. gondii posing a risk for human infection.

Seroprevalence of Toxoplasma gondii and associated risk factors in domestic pigs raised from Cuba

A cross-sectional study was carried out to determine the seroprevalence of Toxoplasma gondii and associated risk factors in pigs in the largest pork-producing region in Cuba. Serum samples from 420 pigs, including 210 sows and 210 post-weaning pigs, were tested for antibodies against T. gondii using a commercial indirect enzyme-linked immunosorbent assay. Anti-T. gondii antibodies were detected in 56 animals (13.3%, 95% CI: 10.1–16.6). A generalized estimating equations model revealed that the risk factors associated with higher seropositivity in pigs were altitude (higher in farm’s location < 250 m above sea level (masl) versus ≥ 250 masl) and age (higher in sows compared to post-weaning pigs). The results indicated that this protozoan parasite is widely distributed on pig farms in the study area, which is a public health concern since the consumption of raw or undercooked pork meat products containing tissue cysts is considered one of the main routes of T. gondii transmission worldwide. Control measures should be implemented to reduce the risk of exposure to T. gondii in pigs in Cuba.

Clusters of Toxoplasmosis in Ganghwa-gun, Cheorwon-gun, and Goseong-gun, Korea

We find out the clusters with high toxoplasmosis risk to discuss the geographical pattern in Gyodong-myeon and Samsan-myeon of Ganghwa-gun, Cheorwon-gun, and Goseong-gun, Korea. Seroepidemiological data of toxoplasmosis surveyed using rapid diagnostic tests for the residents in the areas in 2019 were analyzed to detect clusters of the infection. The cluster was investigated using the SaTScan program which is based on Kulldorff's scan statistic. The clusters were found with P-values in each region analyzed in the program, and the risk and patient incidence of specific areas can be examined by the values such as relative risk and log likelihood ratio. Jiseok-ri and Insa-ri were found to be a cluster in Gyodong-myeon and Seokmo-ri was the cluster in Samsan-myeon. Yangji-ri and Igil-ri were found to be a cluster in Cheorwon-gun and Madal-ri and Baebong-ri were the cluster in Goseong-gun. This findings can be used to monitor and prevent toxoplasmosis infections occurring in vulnerable areas.

The prevalence of Toxoplasma gondii in sheep in China: A systematic review and meta-analysis

Toxoplasmosis is a zoonotic disease caused by Toxoplasma gondii, which is widespread in warm-blooded animals and humans. Currently, many studies regarding T. gondii infection in sheep have been published worldwide. However, there is no meta-analysis of sheep infection in China. In this study, five databases were used to retrieve articles related to T. gondii in China. A total of 59 studies from 1987 to June 30, 2020, have been included. We estimated that the combined prevalence of T. gondii in the selected period was 8.5% (3197/28,099). In the analysis of publication year, the lowest positive rate after 2010 was 7.4% (1883/17,313). Geographically, the highest prevalence of T. gondii in sheep was recorded in Southwest China 19.2% (490/2080). Analysis according to age showed that the prevalence of infection in sheep older than 12 months was significantly (P < 0.05) higher than that in younger animals. The prevalence of T. gondii in sheep farmed by farmers was 7.2% (566/6336), which was higher than 5.3% (660/3121) of large-scale farming, suggesting a role for the feeding and husbandry. We also analyzed the impact of different geographic and climatic factors on the prevalence of T. gondii infection in sheep. The results showed that the prevalence was higher in low altitude, warm, humid, and high rainfall areas. We suggest that appropriate control programs should be formulated according to the differences in reproduction patterns and geographical conditions in different regions to reduce the prevalence of T. gondii among sheep in China.

Outbreaks of clinical toxoplasmosis in humans: five decades of personal experience, perspectives and lessons learned

Background

The protozoan parasite Toxoplasma gondii has a worldwide distribution and a very wide host range, infecting most warm-blooded hosts. Approximately 30% of humanity is infected with T. gondii, but clinical toxoplasmosis is relatively infrequent. Toxoplasmosis has a wide range of clinical symptoms involving almost all organ systems. In most persons that acquire infection postnatally, symptoms (when present) are mild and mimic other diseases such as flu, Lyme disease, Q fever, hematological alterations, or mumps. It is likely that clinical disease is more common than reported. The ingestion of infected meat or food and water contaminated with oocysts are the two main modes of postnatal transmission of Toxoplasma gondii. The infective dose and the incubation period of T. gondii infection are unknown because there are no human volunteer experiments.

Methods

Here, I have critically reviewed outbreaks of clinical toxoplasmosis in humans for the past 55 years, 1966–2020. Information from oocyst-acquired versus meat-acquired infections was assessed separately.

Results

Most outbreaks were from Brazil. There were no apparent differences in types or severity of symptoms in meat- versus oocyst-acquired infections. Fever, cervical lymphadenopathy, myalgia, and fatigue were the most important symptoms, and these symptoms were not age-dependent. The incubation period was 7–30 days. A genetic predisposition to cause eye disease is suspected in the parasites responsible for three outbreaks (in Brazil, Canada, and India). Only a few T. gondii tissue cysts might suffice to cause infection, as indicated by outbreaks affecting some (but not all) individuals sharing a meal of infected meat.

Conclusions

Whether the high frequency of outbreaks of toxoplasmosis in humans in Brazil is related to environmental contamination, poor hygiene, socioeconomic conditions, or to genotypes of T. gondii needs investigation.

Graphic Abstract

DNA-based detection of Leptospira wolffii, Giardia intestinalis and Toxoplasma gondii in environmental feces of wild animals in Korea

Leptospira, Giardia intestinalis and Toxoplasma gondii infections are reported in humans and animals worldwide, but molecular surveillance of these pathogens in Korean wildlife is still limited. Here, we examined the prevalence of these pathogens in environmental feces of Eurasian otters, leopard cats and raccoon dogs using nested PCR followed by DNA sequencing. G. intestinalis was detected in all of three animals, while T. gondii was detected only in leopard cats. Leptospira wolffii was detected in raccoon dog and Eurasian otter. Our results suggest that these animals can act as a reservoir of these zoonotic pathogens. Consistent monitoring of these pathogens in wildlife is needed to prevent from their infections in humans and livestock in Korea.

Toxoplasma gondii infection in wild boars (Sus scrofa) from the State of São Paulo, Brazil: Serology, molecular characterization, and hunter's perception on toxoplasmosis

The consumption of wild boar meat, common in many countries, became popular in Brazil after the hunting of these animals was authorized in 2013. The meat of these animals is often consumed by hunters and their social groups, and their offal is occasionally used as supplemental food in the diet of hunting dogs. Given the high frequency of foodborne diseases related to wild boar meat consumption in other countries, including toxoplasmosis, knowledge on these diseases is essential for risk assessment and elaboration of education campaigns for the exposed public. Thus, this study aimed diagnosing, isolating, and genotyping Toxoplasma gondii in hunted wild boars. For that, we obtained samples of serum and tissues (brain, tongue, diaphragm, and heart) from 26 wild boar hunted in three areas in São Paulo State, Brazil, based on convenience sampling strategy. The serum samples were submitted to the indirect immunofluorescence reaction test (IFAT) test while the tissue samples (n = 22) were used to perform a bioassay in mice to isolate the parasite. The isolated samples were genetically characterized by PCR-RFLP with SAG1, 5' and 3' SAG2, alt.SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico markers. Questionnaires were also formulated and applied to wildlife hunters to assess knowledge about toxoplasmosis. The seroprevalence of T. gondii was 76.9% (20/26), with titers ranging from 16 to 1024. Viable parasites accounted for 4.5% (1/22) of the samples. The ToxoDB #6 genotype of TgJava1 alone was detected. Most interviewed hunters, 84.2% (16/19) consume game meat and a few of them (15.7%; 3/19) prefer undercooked meat. Also, 15.7% (3/19) of the hunters reported supplementing their hunting dogs' diet with wild boar meat and/or offal. As antibodies to T. gondii were detected in 76.9% (20/26) of the studied wild boars, we concluded that infection by T. gondii is frequent in wild boars used for human and animal consumption in the studied areas. Although genotype #6 is commonly found in Brazil in domestic animals, wild animals, and humans, causing everything from mild clinical symptoms to death, this study found, for the first time, the detection of this genotype in wild boars. These results also reaffirm the importance of these animals as a possible source of T. gondii infection for humans and domestic animals.

Seroprevalence of Toxoplasma gondii assayed using Rapid Diagnostic Tests among Residents in Three Counties Adjacent to The Demilitarized Zone, Korea

Toxoplasma gondii seroprevalence have been rapidly increasing in some parts of Korea. We analyzed prevalence of anti-Toxoplasma gondii antibodies, using a rapid diagnostic test (RDT), in the sera of 552 residents in Ganghwa-gun, 661 ones in Cheorwon-gun, and 305 ones in Goseong-gun, Korea in 2019. IgG/IgM RDT mounted with recombinant fragment of major surface antigen (SAG1), glutathione-S-transferase-linker-SAG1A, were applied to the sera. IgG seroprevalence was 28.1% in Ganghwa-gun, 19.5% in Cheorwon-gun and 35.7% in Goseong-gun. Odds ratios comparing Cheorwon vs Ganghwa was 0.63 (P=0.001) and Goesong versus Ganghwa was 1.47 (P=0.01) adjusting age and sex. Goseong had highest seroprevalence among the 3 counties both in crude rates and logistic regression. Although Cheorwon and Goseong are adjacent to the demilitarized zone (DMZ) in Korea, seroprevalence rate was much higher in Goseong. Further investigation on other DMZ-closed areas is necessary whether they have high prevalence rates compared to the other areas. T. gondii prevalence in Korea is still persists; proper health policy should be established.

Murine Model of Primary Acquired Ocular Toxoplasmosis: Fluorescein Angiography and Multiplex Immune Mediator Profiles in the Aqueous Humor

Purpose

To establish a murine model of primary acquired ocular toxoplasmosis (OT) and to investigate the immune mediator profiles in the aqueous humor (AH).

Methods

C57BL/6 mice were perorally infected with Toxoplasma gondii. The ocular fundus was observed, and fluorescein angiography (FA) was performed. The AH, cerebrospinal fluid (CSF), and serum were collected before infection and at 28 days post-infection (dpi); the immune mediator levels in these samples were analyzed using multiplex bead assay.

Results

Fundus imaging revealed soft retinochoroidal lesions at 14 dpi; many of these lesions became harder by 28 dpi. FA abnormalities, such as leakage from retinal vessels and dilation and tortuosity of the retinal veins, were observed at 14 dpi. Nearly all these abnormalities resolved spontaneously at 28 dpi. In the AH, interferon-γ, interleukin (IL)-1α, IL-1β, IL-6, IL-10, IL-12(p40), IL-12(p70), CCL2/MCP-1, CCL3/MIP-1α, CCL4/MIP-1β, CCL5/RANTES, and CXCL1/KC levels increased after infection. All these molecules except IL-1α, IL-4, and IL-13 showed almost the same postinfection patterns in the CSF as they did in the AH. The tumor necrosis factor α, IL-4, and IL-5 levels in the AH and CSF of the T. gondii–infected mice were lower than those in the serum. The postinfection IL-1α, IL-6, CCL2/MCP-1, CCL4/MIP-1β, and granulocyte colony-stimulating factor levels in the AH were significantly higher than those in the CSF and serum.

Conclusions

A murine model of primary acquired OT induced via the natural infection route was established. This OT model allows detailed ophthalmologic, histopathologic, and immunologic evaluations of human OT. Investigation of AH immune modulators provides new insight into OT immunopathogenesis.

Seroprevalence and risk factors of Toxoplasma gondii infection in wild ungulates that cohabit in a natural park with human-animal interaction in the Mediterranean ecosystem

The possibility of Toxoplasma gondii transmitted from game meat to humans is of public health concern. Here we determined seroprevalence and risk factors associated with T. gondii in large game ungulates that cohabit in Sierras de Cazorla, Segura and Las Villas Natural Park (SCSV-NP) (Southern Spain), a natural park with high human-animal interaction. Antibodies against T. gondii in 328 wild ungulates were assayed by the modified agglutination test (MAT ≥ 1:25). Antibodies were found in 39 (11.9%, 95% CI: 8.4-15.4) wild ungulates, with seroprevalence levels of 20.8% in wild boars (Sus scrofa) (5/24), 19.0% in fallow deer (Dama dama) (12/63), 13.9% in Iberian ibex (Capra pyrenaica hispanica) (14/101), 7.9% in red deer (Cervus elaphus) (6/76), and 3.1% in mouflons (Ovis aries musimon) (2/64). Significantly higher seroprevalence was observed in fallow deer and wild boars compared to mouflons. Animals living close to urban areas (<2 km) had 4.6-times higher risk compared to those living at >5 km of urban areas. The results indicate high circulation of T. gondii in wild ungulates in SCSV-NP, which is of animal and public health concern. The increased seroprevalence of T. gondii detected in wildlife ungulates living close to urban areas may increase human infection in those areas if meat from infected animals is consumed raw or undercooked.

Clusters of Toxoplasmosis in Gyodong-Myeon and Samsan-Myeon, Ganghwa-Gun, Korea

The purpose of this study is to find out the clusters with high toxoplasmosis risk to discuss the geographical pattern in 2 islands of Gyodong-myeon and Samsan-myeon in Ganghwa-gun, Korea. Seroepidemiological data of toxoplasmosis surveyed using rapid diagnostic tests for the residents in 2 islands from 2010 to 2013 were analyzed to detect clusters of the infection. The cluster was investigated using the SatScan program which is based on Kulldorff’s scan statistic. The clusters were found with P-values in each region analyzed in the program, and the risk and patient incidence of specific areas can be examined by the values such as relative risk and log likelyhood ratio. Jiseok-ri was found to be a cluster in Gyodong-myeon and Ha-ri was the cluster in Samsan-myeon. This findings can be used to monitor and prevent toxoplasmosis infections occurring in vulnerable areas.

Outbreak of Amazonian Toxoplasmosis: A One Health Investigation in a Remote Amerindian Community

Background:Toxoplasma gondii is a parasite of worldwide importance but its burden in indigenous communities remains unclear. In French Guiana, atypical strains of T. gondii originating from a complex rainforest cycle involving wild felids have been linked to severe infections in humans. These cases of Amazonian toxoplasmosis are sporadic and outbreaks are rarely described. We report on the investigation of an outbreak of acute toxoplasmosis in a remote Amerindian village. We discuss the causes and consequences of this emergence.

Methods: In May 2017, during the rainy season and following an episode of flooding, four simultaneous cases of acute toxoplasmosis were serologically confirmed in two families living the village. Other non-diagnosed cases were then actively screened by a medical team along with epidemiological investigations. Inhabitants from nine households were tested for T. gondii antibodies and parasite DNA by PCR when appropriate. Samples of water, cat feces and cat rectal swabs, soil, and meat were tested for T. gondii DNA by PCR. Positive PCR samples with sufficient DNA amounts were genotyped using 15 microsatellite markers.

Results: Between early May and early July 2017, out of 54 tested inhabitants, 20 cases were serologically confirmed. A fetus infected at gestational week 10 died but other cases were mild. Four patients tested positive for parasite DNA and two identical strains belonging to an atypical genotype could be isolated from unrelated patients. While domestic cats had recently appeared in the vicinity, most families drank water from unsafe sources. Parasite DNA was recovered from one water sample and nine soil samples. Three meat samples tested positive, including wild and industrial meat.

Conclusions: The emergence of toxoplasmosis in such a community living in close contact with the Amazon rainforest is probably multifactorial. Sedentary settlements have been built in the last few decades without providing safe water sources, increasing the risk of parasite circulation in cases of dangerous new habits such as cat domestication. Public health actions should be implemented in these communities such as safe water supply, health recommendations, and epidemiological surveillance of acute toxoplasmosis. A “One Health” strategy of research involving medical anthropology, veterinary medicine, and public health needs to be pursued for a better understanding of the transmission routes and the emergence of this zoonosis.

Review of Successful Control of Parasitic Infections in Korea

Korea had been one of hyperendemic countries of human parasitic infections until 1970s. In 1966, the Law for the Prevention of Parasitic Diseases was enacted, and the nationwide anti-parasitic control program began in 1969. The initiation of the national program was supported financially by Japan. The program included screening of whole students in Korea and treatment of all egg positive cases twice a year, and ended in 1995. In addition to student program, deworming campaign was run in the community, and 8 national status surveys were implemented from 1971 to 2012. Whole helminth egg positive rate was 84.3% in 1971 and decreased to 2.6% in 2012. Ascaris and other intestinal nematodes, Paragonimus, Taenia, and intestinal protozoa had decreased significantly throughout the country, but Clonorchis sinensis and intestinal trematodes are still prevalent locally in endemic areas. Lymphatic filariasis had been endemic in Jeju-do and other southern islands but elimination was endorsed in 2008. The control of parasitic infection in Korea was successful with statistical prevalence data, which can be a benchmarking model. In conclusion, the successful control in Korea could be achieved by social agreement of the priority, professional guidelines and systematic approach with good anthelminthics supply, and simultaneous economic growth.

Potential Role of Plant Extracts and Phytochemicals Against Foodborne Pathogens

Foodborne diseases are one of the major causes of morbidity and mortality, especially in low-income countries with poor sanitation and inadequate healthcare facilities. The foremost bacterial pathogens responsible for global outbreaks include Salmonella species, Campylobacter jejuni, Escherichia coli, Shigella sp., Vibrio, Listeria monocytogenes and Clostridium botulinum. Among the viral and parasitic pathogens, norovirus, hepatitis A virus, Giardia lamblia, Trichinella spiralis, Toxoplasma and Entamoeba histolytica are commonly associated with foodborne diseases. The toxins produced by Staphylococcus aureus, Bacillus cereus and Clostridium perfringens also cause these infections. The currently available therapies for these infections are associated with various limited efficacy, high cost and side-effects. There is an urgent need for effective alternative therapies for the prevention and treatment of foodborne diseases. Several plant extracts and phytochemicals were found to be highly effective to control the growth of these pathogens causing foodborne infections in in vitro systems. The present review attempts to provide comprehensive scientific information on major foodborne pathogens and the potential role of phytochemicals in the prevention and treatment of these infections. Further detailed studies are necessary to evaluate the activities of these extracts and phytochemicals along with their mechanism of action using in vivo models.

Patterns of Transmission and Sources of Infection in Outbreaks of Human Toxoplasmosis

We report on apparent temporal progression of probable sources of infection and transmission routes for global human toxoplasmosis outbreaks as described in published articles. We searched the Scientific Electronic Library Online, Web of Science, PubMed, and Scopus databases for articles on Toxoplasma, toxoplasmosis, and outbreaks. We found that transmission routes for Toxoplasma gondii varied by decade. In the 1960s and 1990s, toxoplasmosis outbreaks mainly occurred through ingestion of cysts in meat and meat derivatives; in the 1980s, through milk contaminated with tachyzoites; in 2000, due to the presence of oocysts in water, sand, and soil; and in 2010, due to oocysts in raw fruits and vegetables. Our study suggests a possible change in the epidemiology of reported toxoplasmosis outbreaks. Because of this change, we suggest that greater attention be paid to the disinfection of vegetables, as well as to the quality of water used for drinking and irrigation.

Prevalence and genetic characterization of Toxoplasma gondii in naturally infected backyard pigs intended for familial consumption in Romania

BACKGROUND

Foodborne toxoplasmosis in humans can be due to the exposure to tissue cysts of Toxoplasma gondii through the consumption of meat, including pork, of infected animals. Traditional Romanian food habits include pork as the preferred meat, while backyard pig rearing remains a common practice in many rural areas of Romania. The aims of the present study were to estimate the prevalence of T. gondii infection in naturally infected backyard pigs slaughtered for familial consumption and to genetically characterize the T. gondii strains obtained.

METHODS

Paired blood and heart samples were collected from 94 backyard pigs, home slaughtered for private consumption. Serum samples were analyzed using the immunofluorescence antibody test (IFAT) for anti-T. gondii antibody detection. Heart samples were screened by polymerase chain reaction (PCR) targeting the 529-bp repeat region (REP529) for T. gondii detection. In addition, heart samples from IFAT positive animals were bioassayed in mice. The T. gondii isolates were genotyped by the analysis of 15 microsatellite markers.

RESULTS

The results showed that almost half of the pigs investigated were T. gondii seropositive (46.8%, 95% confidence interval (CI): 36.4-57.4%) and in more than a quarter of the pigs (26.6%, 95% CI: 18.0-36.7%), the parasite was detected by PCR. Three (3/44) T. gondii strains were isolated from hearts of seropositive pigs and they all belonged to genotype II.

CONCLUSIONS

The present study showed the presence of T. gondii infection in backyard pigs in Romania, which suggests that consumption of pork from animals reared and slaughtered at home may pose a potential threat to human health and should be given attention. In addition, to our knowledge, this is the first study to provide data concerning T. gondii strains circulating in pigs from Romania.

Parasitic infections and medical expenses according to Health Insurance Review Assessment claims data in South Korea, 2011-2018

Introduction

In South Korea, Health Insurance Review and Assessment claims data contain comprehensive information on healthcare services for almost the entire population. The present study used claims data on parasitic diseases from 2011 to 2018, and associated medical expenses to investigate infection trends associated with endemic parasitic diseases in South Korea, including those not monitored by Korea Centers for Disease Control and Prevention.

Methods

Basic data regarding each parasitic disease were curated from the Healthcare Bigdata Hub (http://opendata.hira.or.kr). Ten endemic parasitic diseases, three pandemic protozoan diseases, and three ectoparasitic diseases were evaluated between 2011 and 2018. Data on each parasitic disease included the number of patients of each sex, age range within 5 years, province, and total medical expenses. Heatmap and principal component analysis were performed to visualize the incidence pattern of parasitic diseases by provinces.

Results

Clonorchiasis and pinworm infections decreased remarkably from 6,097 and 4,018 infections in 2011 to 3,008 and 1,988 infections in 2018, respectively. Other endemic parasitic diseases mostly declined or remained steady over the 8-year period, except for anisakiasis, which doubled from 409 in 2011 to 818 in 2018. Provinces close to North Korea had a higher frequency of claims for Plasmodium vivax infection. The highest rate of clonorchiasis was in Gyeongsangnam-do, while that of anisakiasis was in southern Korea. Jeju province had the highest number of claims for cysticercosis, anisakiasis, pinworm infection, and soil-transmitted helminth infections. The total medical expense for anisakiasis was 65 million Korean won (57,000 US$) in 2011, rising to 237 million Korean won (206,000 US$) in 2018. The medical expense for trichomoniasis was 6,063 million won and for scabies was 1,669 million won in 2018. Since the claims data include only data reported by healthcare providers, some discrepancies might have occurred.

Conclusion

Our findings provide the basis for a health policy to reduce further infections and medical expense.

In vivo characterization of a Toxoplasma gondii strain TgCatJpTy1/k-3 isolated from a stray cat in Japan

The Toxoplasma gondii strain TgCatJpTy1/k-3 (K-3), isolated from a stray cat in Tokyo, Japan, is categorized as a type II genotype. Since the K-3 strain is empirically known to form relatively larger cysts and exhibit weak pathogenesis in a mouse, it could serve as a useful model organism to study chronic T. gondii infection in the host. However, a detailed biological characterization of this strain had not been performed. In this study, we thoroughly assessed the K-3 strain in vivo using a mouse model. Tests indicated that pathogenicity of the K-3 strain was lower than that of the PLK strain, a clonal laboratory strain with a moderately pathogenic type II genotype. Further, cyst sizes of the K-3 strain were significantly larger than those of the PLK strain. Interestingly, K-3 cyst sizes in T. gondii-resistant ICR mice were larger than those in T. gondii-susceptible C57BL/6N mice. Our study suggests that the K-3 strain is suitable to study T. gondii cystogenesis and chronic infection, which are currently difficult to analyze using cell-adopted T. gondii strains.

Meta-analysis of Toxoplasma gondii in pigs intended for human consumption in Mainland China

Toxoplasma gondii, is one of the most important foodborne zoonotic pathogens, which can infect virtually all warm-blooded animals, including pigs, and causes severe illness in congenitally infected infants and even death in patients with AIDS. Pigs (Sus scrofa) are one of the most important intermediate hosts of T. gondii, and human transmission occurs through consumption of raw or poorly cooked pork. In this systematic review and meta-analysis, we searched Chongqing VIP, Wanfang, Chinese Web of Knowledge, PubMed, and ScienceDirect databases for published papers regarding Toxoplasma infection in pigs in China, from inception to Oct 29, 2017. Search strings included whether they reported the samples of more than 30 pigs and provided information that allowed us to establish the prevalence of Toxoplasma infection. Moreover, we excluded repeated studies, reviews, other host studies, as well as studies with inconsistent data, incomplete information, those that only provided prevalence data, and those outside of Mainland China. We extracted the numbers of pigs with Toxoplasma infection from the obtained studies, and calculated the pooled prevalence of Toxoplasma infection in the pigs using a random-effects model. The data of 44 articles (including data on 46,723 pigs) were compliant with the standards. The pooled prevalence of T. gondii infection in pigs in China was 29% (95% CI 24-34), with 25% (95% CI 18-32) in pigs sampled before 2010 and 28% (95% CI 21-36) in pigs sampled in 2010 or later. The pooled prevalence of T. gondii in pigs from Northeast China (20%, 95% CI 14-26) was significantly lower than those from other regions (North China: 40%, 95% CI 32-47; Northwest China: 32%, 95% CI 13-51; East China: 30%, 95% CI 20-41; and South China: 35%, 95% CI 26-45; Central China: 23%, 95% CI 14-31; Southwest China: 33%, 95% CI 15-52). The estimated pooled prevalence of T. gondii infection was 36% (95% CI 25-47, 8,018/21,892) in pigs tested by ELISA, 24% (95% CI 19-28, 4,304/18,608) in pigs examined by IHA, and 19% (95% CI 8-31, 1,041/6,223) in pigs detected by other methods. Moreover, 1202 of 7470 piglets were detected as T. gondii-positive, and the prevalence (17%) was lower than that in fattening pigs (25%, OR = 1.28), sows (34%, OR = 2.13), and breeding boars (35%, OR = 2.46). Our findings suggested that toxoplasmosis is common in pigs in Mainland China. It is necessary to monitor the prevalence of T. gondii in pigs, and powerful and effective regulatory measures should be undertaken to reduce human exposure to T. gondii via the consumption of pork.

First Report on Toxoplasma gondii Seroprevalence in Free-Ranging Pigs in Northeastern China

INTRODUCTION

Toxoplasma gondii is the pathogen of toxoplasmosis, which affects a wide range of animal species and humans.

MATERIALS AND METHODS

In the present study, a serological investigation was undertaken to determine the seroprevalence of T. gondii infection in free-ranging pigs in northeastern China. A total of 806 serum samples were collected from free-ranging pigs in 6 cities in Liaoning, Jilin, and Heilongjiang Provinces.

RESULTS

Among them, 163 serum samples (20.22%) were detected T. gondii positive by indirect hemagglutination test (IHA). In each administrative district, the prevalence ranges from 12.99 to 22.22%. It was found that sample collection year and season were associated with T. gondii infection. Samples collected in 2015 and 2016 had had higher positive rate compared to those collected in 2017. Samples collected in summer and autumn also have higher positive rate than those in winter.

CONCLUSION

This is the first report on T. gondii seroprevalence in free-ranging pigs in northeastern China, which adds the epidemiological data of T. gondii infection in free-ranging pigs in China. These results indicated that free-ranging pigs in Liaoning, Jilin, and Heilongjiang Provinces are exposed to T. gondii, which is a significant threat to local pig industry as well as public health. It is necessary to take relevant comprehensive measures to prevent and control T. gondii infection in free-ranging pigs in these regions.

A review on inactivation methods of Toxoplasma gondii in foods

Toxoplasmosis is an infection caused by Toxoplasma gondii, a widespread zoonotic protozoan which poses a great threat to human health and economic well-being worldwide. It is usually acquired by ingestion of water contaminated with oocysts from the feces of infected cats or by the ingestion of raw or undercooked foodstuff containing tissue cysts. The oocyst can contaminate irrigation water and fresh edible produce. It is estimated that approximately one-third of the human population worldwide harbor this parasite. Infection with T. gondii is an important cause of diseases of the central nervous system and the eye in immunocompromised and immunocompetent individuals. The purpose of this study was to evaluate the efficacy and applicability of thermal (heating, cooking, freezing and low temperature), non-thermal (high pressure processing, ionizing irradiation and curing) and chemical and biochemical (disinfection, essential oils and biochemical methods such as enzymes, nanoparticles, antibiotics and immune response) treatments for the inactivation, inhabitation or to kill T. gondii in foodstuff intended for public consumption and under experimental conditions.

Prevalence of Toxoplasma gondii and Potentially Zoonotic Helminths in Wild Boars (Sus scrofa) Hunted in Central Italy

Our aim was to evaluate the risk of human toxoplasmosis via meat consumption from wild boars by estimating the seroprevalence of Toxoplasma gondii in animals hunted in central Italy. Using a modified agglutination test, 213 sera from wild boars were examined for anti-Toxoplasma IgG antibodies. Diaphragm samples (n=65) from seropositive and seronegative animals were tested by nested-PCR to detect T. gondii DNA. Toxoplasma DNA from diaphragms was genotyped by PCR-RFLP using 12 genetic markers. Moreover, the aim of the study was also to identify helminth infections of wild boars in the selected area and to evaluate their hazard for humans. Examination of sera revealed a seroprevalence of 12.2%. Only one T. gondii strain could be genotyped from a seropositive animal and PCR-RFLP revealed that it belonged to type II. Analysis of 50 samples of faeces and 32 small intestines revealed that 78% and 15.6% of the samples harboured parasites, respectively, with the occurrence of parasites potentially dangerous for humans. These latter included Ascaris suum, Macracanthorhynchus hirudinaceus, Trichuris suis, and Metastrongylus spp. A significant association was found between coprological positivity and male sex. These results indicate that T. gondii infection may be present in wild boar tissues and consumption of undercooked or raw wild boar meat may expose humans to risk of toxoplasmosis in the study area. Furthermore, the study highlights that wild boars are hosts of helminths of veterinary and medical importance transmissible to pigs and humans.

High seroprevalence of Toxoplasma gondii in goats in Jharkhand state of India

Toxoplasmosis, caused by Toxoplasma gondii, is an important food borne zoonosis worldwide. Although goat meat constitutes an important dietary protein source, improperly cooked meat is a potential source of infection to humans. Data on prevalence of toxoplasma in goat is scanty from India. Serological detection is the practical option for prevalence studies on T. gondii, as no biological stage of the parasite is present in the clinical materials from the intermediate hosts. The present study was undertaken in the Jharkhand state of India which is largely inhabited by economically weaker aborigine population, who depend largely on animal husbandry for livelihood. A total of 445 serum samples were collected for testing, which represented goats under intensive and free range system of rearing. T. gondii specific IgG antibodies were detected in 42.47% (n = 189) samples by rSAG1 based indirect ELISA. The seroprevalence data were analyzed in respect of age, sex, breed of the goats and altitude of the study area as well as rearing conditions of the animals to establish correlation, if any. Though age and sex of the animals had a direct correlation with infection, the same could not be established with the other factors. The sensitivity and specificity of the diagnostic ELISA were compared with IFAT, as well as with a commercially available ELISA kit. The rSAG1-ELISA had 92.66% sensitivity and 90.67% specificity with a positive predictive value of 86.77% and negative predictive value 94.92% when compared with IFAT, whereas when compared with the commercial ELISA kit, 87.50% sensitivity and 90.91% specificity with a positive predictive value of 91.30% and negative predictive value 86.96% were observed. Inter rater agreement (kappa) was calculated. rSAG1-ELISA showed good agreement with IFAT (kappa = 0.824) and commercially available ELISA Kit (kappa = 0.783). Receiver Operating Characteristics (ROC) curve analysis, revealed a larger area under curve (AUC) of 0.99 (95%CI, 0.97-1.0) when compared with IFAT as gold standard and a highest relative sensitivity 91.30 (95% CI 72-98.3) and specificity 1.0 (95% CI 85.2-100) for the cut off value of 0.6005. The present study revealed high seroprevalence of T. gondii in goats from Jharkhand, which has public health significance.

Seroprevalence of Toxoplasma gondii infection in arthritis patients in eastern China

Background

There is accumulating evidence for an increased susceptibility to infection in patients with arthritis. We sought to understand the epidemiology of Toxoplasma gondii infection in arthritis patients in eastern China, given the paucity of data on the magnitude of T. gondii infection in these patients.

Methods

Seroprevalence of T. gondii infection was assessed by enzyme-linked immunosorbent assay using a crude antigen of the parasite in 820 arthritic patients, and an equal number of healthy controls, from Qingdao and Weihai cities, eastern China. Sociodemographic, clinical and lifestyle information on the study participants were also obtained.

Results

The prevalence of anti-T. gondii IgG was significantly higher in arthritic patients (18.8%) compared with 12% in healthy controls (P < 0.001). Twelve patients with arthritis had anti-T. gondii IgM antibodies – comparable with 10 control patients (1.5% vs 1.2%). Demographic factors did not significantly influence these seroprevalence frequencies. The highest T. gondii infection seropositivity rate was detected in patients with rheumatoid arthritis (24.8%), followed by reactive arthritis (23.8%), osteoarthritis (19%), infectious arthritis (18.4%) and gouty arthritis (14.8%). Seroprevalence rates of rheumatoid arthritis and reactive arthritis were significantly higher when compared with controls (P < 0.001 and P = 0.002, respectively). A significant association was detected between T. gondii infection and cats being present in the home in arthritic patients (odds ratio [OR], 1.68; 95% confidence interval [CI]: 1.24 – 2.28; P = 0.001).

Conclusions

These findings are consistent with and extend previous results, providing further evidence to support a link between contact with cats and an increased risk of T. gondii infection. Our study is also the first to confirm an association between T. gondii infection and arthritis patients in China. Implications for better prevention and control of T. gondii infection in arthritis patients are discussed.

Trial registration

This is an epidemiological survey, therefore trial registration was not required.

Electronic supplementary material

The online version of this article (10.1186/s40249-017-0367-2) contains supplementary material, which is available to authorized users.

Seroprevalence of Toxoplasmosis Detected by RDT in Residents near the DMZ (demilitarized zone) of Cheorwon-gun, Gangwon-do, Korea

Seroprevalence of Toxoplasma gondii infection among the residents of Cheorwon-gun, Gangwon-do, Korea, which partly includes the demilitarized zone (DMZ), were surveyed for 4 years and evaluated by RDT using recombinant fragment of major surface antigen (SAG1A). Sera from 1336, 583, 526, and 583 adult residents were collected on a yearly basis from 2010 to 2013, respectively. The total positive seroprevalence was 19.3, 21.9, 23.4, and 26.8% from 2010 to 2013, respectively. The positive seroprevalence in men (23.6, 27.5, 29.5, 34.6%) was far higher than women (14.1, 18.3, 19.4, 21.4%), from 2010 to 2013, respectively. This high seroprevalence of toxoplasmosis in Cheorwon-gun may have been influenced in part by its geographical locality of the area as it includes the DMZ, where civilian access is strictly limited, thus creating a relatively isolated area that is a well-preserved habitat. Further research is necessary to study the epidemiology of toxoplasmosis in this area.

Molecular detection and genetic characterization of Toxoplasma gondii in farmed raccoon dogs (Nyctereutes procyonoides) in Shandong province, eastern China

Toxoplasma gondii is a successful opportunistic parasite, affecting a wide range of vertebrate animals and humans. Genetic diversity of T. gondii in raccoon dogs (Nyctereutes procyonoides) is of great importance to understand the transmission of T. gondii in the environment. However, no information is available about the distribution of genetic diversity of T. gondii infection in raccoon dogs. This study was conducted to estimate the prevalence and genetic characterization of T. gondii from raccoon dogs in Shandong province, eastern China. A total of 314 brain tissue samples of raccoon dogs were collected and genomic DNA was extracted and assayed for T. gondii infection using semi-nested PCR targeting B1 gene. The positive DNA samples were typed at 10 genetic markers (SAG1, SAG2(5'+3' SAG2, alter.SAG2), SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico) by multiplex multilocus nested polymerase chain reaction-restriction fragment length polymorphism (Mn- PCR-RFLP) technology. Thirty-five (11.15%) of 314 DNA samples were detected positive. Only six samples were completely typed at all genetic loci, and these samples represented ToxoDB genotype#9. Two sample were typed at 9 genetic loci and one was typed at 8 genetic loci, all of them represented Type I. To our knowledge, this is the first report of genetic characterization of T. gondii in raccoon dogs in China. These results revealed the existence of genetic diversity of T. gondii in raccoon dogs in China. These data provided base-line information for controlling T. gondii infection in raccoon dogs.

Seroprevalence of Toxoplasmosis with ELISA and Rapid Diagnostic Test among Residents in Gyodong-do, Inchon city, Korea: A Four-Year Follow-up

ELISA has been used for the diagnosis of toxoplasmosis, but it is being gradually replaced by a rapid diagnostic test (RDT). We compared and analyzed ELISA and RDT results using the sera collected during 4 consecutive years from residents of Gyodong-do (Island), Incheon-city, Korea. Sera from 921, 993, 940, and 838 adult residents were collected on a yearly basis (2010-2013). ELISA was performed by using a crude extract of T. gondii RH strain antigen and IgG/IgM RDT mounted with recombinant fragment of major surface antigen (SAG1), GST-linker-SAG1A, were applied to the sera. Comparison between groups was analyzed by the Student's t-test. The positive seroprevalence surged from 14.7% (135/921, 2010), 23.1% (231/993, 2011), 23.6% (222/940, 2012), and 32.1% (269/838, 2013) by ELISA. In contrast, RDT showed a more moderate increasing trend from 21.7% (200/921, 2010), 25.5% (253/993, 2011), 28.9% (272/940, 2012) and 33.1% (277/838, 2013). Discrepancies between ELISA and RDT were noted near the cut-off value. At the OD 0.15-0.24 range, RDT could detect 16.1% (169/1051) more positives, which suggests an early or acute toxoplasmosis, but at the OD 0.25-0.34 range, ELISA could detect 35.9% (92/256) more positives of possible chronic infections. Over the OD > 0.35 ELISA and RDT agreed in the majority of the cases. This surge in seroprevalence may be caused by the organic agriculture in addition to eating behavior or increase in pets among Koreans. These facts may be applied on a full-scale national survey using RDT to supplement ELISA to define the characteristics of the infection.

A Review of Zoonotic Infection Risks Associated with the Wild Meat Trade in Malaysia

The overhunting of wildlife for food and commercial gain presents a major threat to biodiversity in tropical forests and poses health risks to humans from contact with wild animals. Using a recent survey of wildlife offered at wild meat markets in Malaysia as a basis, we review the literature to determine the potential zoonotic infection risks from hunting, butchering and consuming the species offered. We also determine which taxa potentially host the highest number of pathogens and discuss the significant disease risks from traded wildlife, considering how cultural practices influence zoonotic transmission. We identify 51 zoonotic pathogens (16 viruses, 19 bacteria and 16 parasites) potentially hosted by wildlife and describe the human health risks. The Suidae and the Cervidae families potentially host the highest number of pathogens. We conclude that there are substantial gaps in our knowledge of zoonotic pathogens and recommend performing microbial food safety risk assessments to assess the hazards of wild meat consumption. Overall, there may be considerable zoonotic risks to people involved in the hunting, butchering or consumption of wild meat in Southeast Asia, and these should be considered in public health strategies.

Mycobacterium tuberculosis Infection in a Domesticated Korean Wild Boar ( Sus scrofa coreanus)

Tuberculosis, a chronic progressive disease, has been reported in bovine, swine, and primate species. Here, we report the first case of Mycobacterium tuberculosis infection in a Korean wild boar ( Sus scrofa coreanus). The owners this domesticated boar brought it to the Gyeongbuk Veterinary Service Laboratory in Korea after it was found dead and severely emaciated. Demarcated yellowish white nodules were found around the larynx and retropharyngeal lymph node during necropsy. The lungs had diffuse fibrinous pleuritis, severe congestion, and scattered nodules. More nodules were found in the spleen. Tuberculosis is characterized by massive macrophage infiltration and central caseous necrosis; both characteristics were found in the lungs. Histopathologic examination revealed that the alveolar lumen had marked fibrosis and exudates. Examination of the fluid revealed extensive macrophage permeation. To confirm a Mycobacterium infection, PCR was performed using two primer sets specific to the rpoB gene of Mycobacterium; Mycobacterium was detected in the lungs and spleen. To identify the species of Mycobacterium, immunohistochemical evaluation was performed using antibodies against Mycobacterium tuberculosis and Mycobacterium bovis . The results revealed immunoreactivity against M. tuberculosis but not against M. bovis . The consumption of undercooked or raw meat from game animals may expose humans and other animals to sylvatic infection. Consequently, Koreans who ingest wild boar may be at risk of a tuberculosis infection. To reduce the risk of foodborne infection and maintain public health, continuous monitoring and control strategies are required.

Serological and Molecular Detection of Toxoplasma gondii and Babesia microti in the Blood of Rescued Wild Animals in Gangwon-do (Province), Korea

Infections of Toxoplasma gondii and Babesia microti are reported in many wild animals worldwide, but information on their incidence and molecular detection in Korean wild fields is limited. In this study, the prevalence of T. gondii and B. microti infection in blood samples of 5 animal species (37 Chinese water deer, 23 raccoon dogs, 6 roe deer, 1 wild boar, and 3 Eurasian badgers) was examined during 2008–2009 in Gangwon-do (Province), the Republic of Korea (=Korea) by using serological and molecular tests. The overall seropositivity of T. gondii was 8.6% (6/70); 10.8% in Chinese water deer, 4.3% in raccoon dogs, and 16.7% in roe deer. PCR revealed only 1 case of T. gondii infection in Chinese water deer, and phylogenic analysis showed that the positive isolate was practically identical to the highly pathogenetic strain type I. In B. microti PCR, the positive rate was 5.7% (4/70), including 2 Chinese water deer and 2 Eurasian badgers. Phylogenetic analysis results of 18S rRNA and the β-tubulin gene showed that all positive isolates were US-type B. microti. To our knowledge, this is the first report of B. microti detected in Chinese water deer and Eurasian badger from Korea. These results indicate a potentially high prevalence of T. gondii and B. microti in wild animals of Gangwon-do, Korea. Furthermore, Chinese water deer might act as a reservoir for parasite infections of domestic animals.

Toxoplasma gondii Infection in Farmed Wild Boars (Sus scrofa) in Three Cities of Northeast China

The apicomplexan protozoan parasite Toxoplasma gondii is a widely distributed etiological agent of foodborne illness. This parasite can cause production losses in livestock and serious disease in humans through consumption of contaminated meat. Pig meat is the most likely source of human infection, and wild boars may play a role in the transmission of T. gondii by serving as a reservoir host. This study aimed to investigate the seroprevalence of antibodies to T. gondii among farmed wild boars in China. In an 11-month survey, a total of 882 serum samples were obtained from farmed wild boars from three cities (Jilin City, Siping City, and Baishan City) in Jilin province, Northeast China and were tested for antibodies specific for T. gondii. Using modified agglutination test and a cutoff titer of 1:25, the prevalence of T. gondii infection in the examined samples was 10.0% (88 of 882). The highest seroprevalence was observed in animals from Jilin city (15.3%, 43/281) and followed by Siping (11.4%, 30/263) and Baishan (4.4%, 15/338). Logistic regression analysis revealed a significant correlation between the investigated geographic region and T. gondii infection. In addition, prevalence was higher in females compared to males, and the highest prevalence was detected in piglets. These findings indicate that farmed wild boars may become a source of foodborne toxoplasmosis, posing a food safety threat to the public health in the investigated areas. Implementation of effective measures to control T. gondii infection in farmed wild boars in China may be warranted.

Quantitative Microbial Risk Assessment for Campylobacter Foodborne Illness in Raw Beef Offal Consumption in South Korea

This study evaluated the risk of Campylobacter foodborne illness caused by the intake of raw beef offal in South Korea. The prevalence of Campylobacter spp. in raw beef offal (liver and tripe) was investigated by plating samples on modified charcoal-cefoperazone-deoxycholate agar with Preston enrichment broth. Data were collected about storage temperature and length of storage of raw beef offal, and probabilistic distributions for the data were determined, using @RISK software. Predictive models were developed to describe the fate of Campylobacter in raw beef offal, and the amount and frequency of consumption and dose-response model were surveyed. Subsequently, these data were used to estimate the risk of Campylobacter foodborne illness caused by the intake of raw beef offal. Of 80 beef offal samples, 1 (1.25%) was contaminated with Campylobacter jejuni . Predictive models were used for exposure assessment. An exponential distribution was selected to represent beef offal consumption by people who eat this occasionally, with a mean of 60.2 g and 3.6% monthly consumption frequency. Simulations using @RISK predicted that the probability of Campylobacter foodborne illness per person per month is 1.56 × 10^-5 for home consumption and 1.74 × 10^-5 for restaurant consumption in South Korea, which indicates the risk of Campylobacter foodborne illness by intake of raw beef offal in South Korea.

Toxoplasma gondii in raw and dry-cured ham: The influence of the curing process

The aim of this work was to analyze Toxoplasma gondii in raw hams by mouse bioassay and to evaluate the effect of curing on the viability of the parasite to assess the risk of infection from eating dry-cured ham. After a serology study of 1200 pigs in Aragón (Spain), forty-one naturally infected pigs with different serological titers against T. gondii were selected. Two cured periods (9 and 12 months) were evaluated as well as the influence of the physicochemical composition of hams on T. gondii survival. Although the parasite burden was low, a high number of seropositive pigs with Toxoplasma tissues cysts in raw hams were found (31.6%). Viability of T. gondii was influenced by the curing, with statistically significant differences between fresh and cured hams (p < 0.001). The viability was higher in hams cured for 9 months compared to those cured for 12 months. However, this period of curing resulted in the reduction but not in a complete elimination of the risk. Thus, from a public health point of view, under the conditions of this study it is safer to consume dry-cured ham with periods of curing higher than 12 months. Analysis of physicochemical results did not identify any variable with significant influence on the presence and viability of T. gondii in cured ham, but loss of viability of T. gondii was observed in hams with a lower fat content. Further research is required to validate combinations of salts concentration and time of curing that can be used as preventive measures in the HACCP system of dry-cured ham industry.

High Seroprevalence of Toxoplasmosis Detected by RDT among the Residents of Seokmo-do (Island) in Ganghwa-Gun, Incheon City, Korea

Seroprevalence of Toxoplasma gondii infection among the residents of Seokmo-do (Island) in Ganghwa-gun, Incheon, Korea was surveyed for 4 years by a rapid diagnostic test (RDT) using recombinant fragment of major surface antigen (SAG1), GST-linker-SAG1A. Sera from 312, 343, 390, and 362 adult residents were collected on a yearly basis from 2010 to 2013, respectively. Total positive seroprevalence regardless of gender was 29.2, 35.3, 38.7, and 45.3% from 2010 to 2013, respectively. Positive seroprevalence in male adults was 43.9, 48.2, 45.4, and 55.3%, which was far higher than that of the corresponding female adults which was 20.7, 29.2, 33.9, and 38.9%, from 2010 to 2013, respectively. This high seroprevalence of toxoplasmosis in Seokmo-do may have been caused in part by peculiar changes in the toxoplasmic environment of the island as it is a relatively isolated area preserving its natural habitat while also being connected by a bridge to the mainland. Further study is necessary to find out symptomatic patients and to confirm the risk factors.