Definitive Hosts Research Articles

Parasite-host relations and new reports of helminths for Rhinella dorbignyi (Duméril & Bibron, 1841) (Anura: Bufonidae) from Neotropical region

This study aimed to analyze helminth assemblage in Rhinella dorbignyi regarding host gender, size and mass in two sampling sites in southern Brazil, and to report new parasite associations. Anurans (n = 100) were collected in two localities from Rio Grande do Sul (RS) state, Brazil, from 2017 to 2020. Nineteen taxa (adults and larval forms) belonging to Nematoda, Acanthocephala, Digenea, and Cestoda were found in different infection sites. Cosmocercidae gen. Spp., Physaloptera liophis, Catadiscus sp., and Cylindrotaenia americana were the dominant taxa in helminth assemblage. Female anurans showed higher helminth species richness than males considering the total sample (two localities) or one of the two localities. However, prevalence and mean intensity of infection did not show any significant difference between genders. Mean intensity of infection was significantly higher (19.52) in Laranjal locality. Host body size does not influence helminth abundance, as infections did not show significant correlation snout-vent length (SVL) nor body mass (BM) of anurans. The findings reveal anurans of R. dorbignyi may be intermediate, paratenic and definitive host for these parasites. Plagiorchioidea helminths (Digenea), Physaloptera liophis, larvae of Acuariidae and Spiroxys sp. (Nematoda), and cystacanth of Lueheia sp. (Acanthocephala) constitute new records for R. dorbignyi. Additionally, this is the first record of Cylindrotaenia americana larvae in this host species. Resulting information increases the knowledge on biodiversity and parasite-host relations and may help future conservation programs developed in ecosystems in the extreme south of Brazil.

Assessment of Fasciola and Paramphistomes co-infection in large ruminants through faecal egg counts around Taiping, Malaysia.

Emerging cases of Fasciola and Paramphistomes co-infection have been reported, especially in tropical regions. Thisis due to Fasciola and Paramphistomes sharing biological factors which influence the pattern of transmission, especially in faecal egg shedding due to interaction and competition in the definitive host. Most reports surveyed the occurrence of fasciolosis in ruminants with a lack of observation of faecal egg distribution. Therefore, present study is aimed to assess the distribution of Fasciola and Paramphistomes faecal egg count (fec) in co-infected large ruminants in Larut, Matang, and Selama areas (Taiping). A total of 371 faecal samples were collected at random from 23 ruminant herds. Flukefinder® sedimentation was used to quantify the Fasciola and Paramphistomes eggs. Descriptive analyses were performed to determine the prevalence of co-infections, and Spearman correlation analysis was used to correlate the fec. Overall, the prevalence of Fasciola and Paramphistomes co-infection was 23.7% (n=89/371) in Taiping. Prevalence of paramphistomosis was always higher than fasciolosis in overall and single infection, with 46.9% (n=174/371) and 22.9% (n=85/371) compared to 36.9% (n=137/371) and 12.9% (n=48/371) respectively. Egg per gram (epg) of both parasites were positively skewed with a median of 1.5 epg in fasciolosis and 10.5 epg in paramphistomosis. Spearman correlation analysis of the epg in co-infected bovine was found to have a moderately positive correlation with rs=0.39 (p-value<0.01). The recent study observed a moderate prevalence of Fasciola and Paramphistomes coinfection in a large ruminant population from Taiping, with the prevalence of paramphistomosis being higher than fasciolosis. Hence, this suggests that infection with one of these parasites increases the chance of infection with another. There is a need to integrate fec in parasite surveillance to monitor the trend of parasite transmission. Findings in the present study could tailor control strategies, especially for fasciolosis to limit the economic loss and prevent zoonotic transmission.

Effects of Cymatocarpus solearis (Trematoda: Brachycoeliidae) on its second intermediate host, the Caribbean spiny lobster Panulirus argus.

Many digenean trematodes require three hosts to complete their life cycle. For Cymatocarpus solearis (Brachycoeliidae), the first intermediate host is unknown; the Caribbean spiny lobster Panulirus argus is a second intermediate host, and the loggerhead turtle Caretta caretta, a lobster predator, is the definitive host. Trophically-transmitted parasites may alter the behavior or general condition of intermediate hosts in ways that increase the hosts' rates of consumption by definitive hosts. Here, we examined the effects of infection by C. solearis on P. argus by comparing several physiological and behavioral variables among uninfected lobsters (0 cysts) and lobsters with light (1-10 cysts), moderate (11-30 cysts), and heavy (>30 cysts) infections. Physiological variables were hepatosomatic index, growth rate, hemocyte count, concentration in hemolymph of cholesterol, protein, albumin, glucose, dopamine (DA) and serotonin (5-HT). Behavioral variables included seven components of the escape response (delay to escape, duration of swimming bout, distance traveled in a swimming bout, swim velocity, acceleration, force exerted, and work performed while swimming). There was no relationship between lobster size or sex and number of cysts. Significant differences among the four lobster groups occurred only in concentration of glucose (lower in heavily infected lobsters) and 5-HT (higher in heavily and moderately infected lobsters) in plasma. As changes in 5-HT concentration can modify the host's activity patterns or choice of microhabitat, our results suggest that infection with C. solearis may alter the behavior of spiny lobsters, potentially increasing the likelihood of trophic transmission of the parasite to the definitive host.

Toxoplasma gondii in small mammals in Romania: the influence of host, season and sampling location

BackgroundToxoplasma gondii is a protozoan parasite that infects a large spectrum of warm-blooded animals, including humans. Small rodents and insectivores play an important role in the epidemiology of T. gondii and may serve as a source of infection for both, domestic and wild definitive felid hosts. Factors influencing the occurrence of T. gondii in wild small mammals are unknown, despite the fact that many intermediate host species are identified. We have used small mammals (Rodentia and Lipotyphla) captured over two years in various habitats, both in urbanised and in natural landscapes. We assessed the importance of land-use, season and host ecology on T. gondii infection.ResultsWe examined 471 individuals belonging to 20 small mammal species, collected at 63 locations spread over wide altitude, habitat and land-use ranges from Romania. Heart tissue samples were individually analysed by PCR targeting the 529 bp repetitive DNA fragment of T. gondii. The overall prevalence of infection was 7.3%, with nine species of rodents and two species of shrews being found to carry T. gondii DNA. Five species showed high frequency of infection, with the highest prevalence found in Myodes glareolus (35.5%), followed by Spermophilus citellus (33.3%), Sorex minutus (23.1%), S. araneus (21.7%) and Micromys minutus (11.1%). Adults seemed more often infected than young, however when controlling for season, the difference was not significant, as in spring both adults and young showed higher infection rates, but more adults were sampled. Contrary to our expectations, urban/rural areas (with their implicit high density of domestic feline presence) had no effect on infection prevalence. In addition, neither habitat, nor land-use at sampling sites was important as only geographical location and host species were contributing factors to the infection risk.ConclusionsHigh prevalence of T. gondii infection showed a highly localised, patchy occurrence, with long living and higher mobility host species being the most common carriers, especially during autumn.

Canine Toxoplasma Gondii and Distemper Virus Co-Infection in a Dog with Neuro-ophthalmologic Signs from Córdoba, Argentina

Toxoplasmosis is caused by the globally distributed parasitic intracellular protozoan Toxoplasma gondii (phylum Apicomplexa, family Sarcocystidae). Domestic cats and other felids are the definitive hosts.

Elucidating Spirocerca lupi spread in the Americas by using phylogenetic and phylogeographic analyses

Spirocerca lupi is a parasitic nematode of domestic and wild canids of the world. This nematode induces esophageal spirocercosis and may eventually lead to carcinomas, aortic aneurisms, and death of the animal. Two genotypes of S. lupi have been described based on specimens from Europe, Asia, Africa, and Oceania, but no profound analysis has been conducted with S. lupi from the Americas. To study this, S. lupi specimens isolated from domestic dogs from Mexico, Costa Rica, and the United States, were molecularly characterized using 18S rDNA and cox1 fragments. Bayesian inference (BI) phylogenetic trees, Templeton-Crandall-Sing (TCS) haplotype networks and Principal coordinate analysis on nucleotide distances were constructed for each locus separately. In addition, a phylogeographic study using a fragment of the cox1 gene was used to infer the evolutionary history of the genus. BI cox1 trees grouped S. lupi from the Americas in genotype 1, together with Israeli specimens, and showed a high nucleotide identity with those worms. In the TCS network, American specimens clustered next to Israeli S. lupi. Furthermore, the 18S rDNA gene fragment separated Costa Rican worms from African, Asian, and European specimens and other species of the family Spiruridae. Interestingly, the phylogeographic analysis suggested that the origin of S. vulpis was in Europe, and it later diverged into S. lupi that spread first to Africa, then to Asia and finally to the Americas. Therefore, we suggest that the worms from the American continent might have originated from Asia by dispersion of infected intermediate, paratenic or definitive hosts.

AP2XII-1 is a negative regulator of merogony and presexual commitment in Toxoplasma gondii.

Sexual development is vital for the transmission, genetic hybridization, and population evolution of apicomplexan pathogens, which include several clinically relevant parasites, such as Plasmodium, Eimeria, and Toxoplasma gondii. Previous studies have demonstrated different morphological characteristics and division patterns between asexual and sexual stages of the parasites. However, the primary regulation is poorly understood. A transition from the asexual to the sexual stage is supposedly triggered/accompanied by rewiring of gene expression and controlled by transcription factors and chromatin modulators. Herein, we discovered a tachyzoite-specific transcriptional factor AP2XII-1, which represses the presexual development in the asexual tachyzoite stage of T. gondii. Conditional knockdown of AP2XII-1 perturbs tachyzoite proliferation by endodyogeny and drives a transition to a morphologically and transcriptionally distinct merozoite stage. The results also suggest a hierarchical transcriptional regulation of sexual development by AP2 factors and provide a path to culturing merozoites and controlling inter-host transmission of T. gondii.

Fasciolosis Prevalence in Sacrificial Cattle of West Sumatra, Indonesia

Fasciola is a species of the trematode genus that can cause devastating parasitic disease, namely fasciolosis. Fasciola spp. infestation can affect ruminants, such as cows, buffaloes, goats, and sheep, resulting in economic losses to livestock owners. Ruminants are the definitive host for the Fasiola species. This cross-sectional research was conducted on Eid al-Adha/Qurban in July 2022 to determine the prevalence of fasciolosis in sacrificial cattle in Fifty Cities District, West Sumatra, Indonesia. A total of 106 samples of sacrificial cattle liver from the abattoir were investigated. Examination of the liver for the presence of Fasciola spp. was carried out by postmortem examination by removing the liver from the abdominal cavity immediately after slaughter. The livers of all sacrificial cattle were examined by systematic inspection, palpation, and incision for Fasciola spp. infestation. Necropsy results of samples indicated the prevalence of Fasciola spp. (36.79%), which was higher in female animals, compared to males. Based on age, the highest prevalence was at the age of &gt; 4 years, (52.95%), followed by 2 years (39.62%) and 3 years (25.00%). Regarding the cattle breed, the highest prevalences were indicated in Pesisir cattle (47.61%), Simmental cattle (44.44%), Bali cattle (37.28%), Ongole cattle (20%), and Limousine cattle (14.28%). This study revealed that fasciolosis in sacrificial animals in Fifty Cities, West Sumatra, was influenced by gender. Therefore, the findings of this study suggest improving treatment protocol for the prevention of fasciolosis in sacrificial animals.

Review on the Prevalence and Associated Risk Factors of Parasitic Zoonosis in Ethiopia: Taeniasis

Parasitic foodborne infections of humans may involve both protozoan and helminth species of internal parasites. The route of infection is normally consumption of the parasite’s natural hosts as a human food item. Taeniasis is a parasitic zoonotic disease caused by the adult stage of large tapeworms that live in the intestines of human hosts. Bovine cysticercosis is a food borne disease caused by Taenia saginata with humans as the final host and cattle as the intermediate host. Infection of human by Taenia saginata occurs through ingestion of raw or undercooked meat containing Cysticercus Bovis while; infection of cattle with Cysticercus Bovis occurs through ingestion of Taenia saginata eggs. The parasite population of these species consists of three distinct sub populations: adult Tapeworms in the definitive host (man), larvae (Cysticercus or metacestodes) in the intermediate host (pigs or cattle), and eggs in the environment. The most common causative agent in Ethiopia is the beef tapeworm, Taenia saginata, which has the cow as its intermediate host. The other tapeworm that can cause taeniasis (Taenia solium) has pigs as its intermediate host, but they are not so common in Ethiopia. Taeniasis due to beef tapeworm is highly prevalent in Ethiopia due to the widespread habit of eating raw beef (kitfo in Amharic, Figure 38.5) and poor sanitary conditions. Defaecation in open fields in grazing lands, disposal of raw human sewage in rivers and its use as a fertiliser, facilitate the spread of taeniasis. The highest cases of taeniasis are found in the towns of Northern and Eastern Ethiopia.

A Case Report of Coenurus Cerebralis in a Goat at Dembecha District of Amhara Region, Ethiopia

The Animal Health Institute received a report of an outbreak from Amhara Regional State, West Gojam zone, Dembecha district, with an unknown etiological agent on caprine death in February 2023. With the objective to conduct investigations and ascertain the reason for the caprine death, a team of experts was deputed to the affected area. Goat exhibiting seizures, lateral recumbency, and appetite loss during a clinical examination, symptoms of a central nervous system disorder including paddling, convulsions, and unconsciousness were noted. Based on clinical sign and presence of definitive hosts at the area the case has been defined for coenurosis cerebralis. For further confirmatory diagnosis postmortem inspection for the brain was undertaken. Cysts were found during necropsy in the left hemisphere’s occipital lobe. The cysts were filled with a clear fluid, and the inner layer of the cysts had several clusters of scolice growing out of it. Larval form of Taenia multiceps, known as Coenurus cerebralis, is found in the small intestines of dogs and other carnivores in the wild. Worldwide, coenurosis is endemic, and it is particularly prevalent in Ethiopia’s highlands, where there are many sheep. Commonly occurs in the life cycle of dogs and small ruminants. The larvae of this parasite are found in the brain and spinal cord of intermediate hosts, while the adult stage of the parasite lives in the small intestine of dogs, foxes, coyotes, and jackals. The intermediate hosts become infected when the dog eats the brain containing the Coenurus cyst, which then develops into Taenia multiceps and begins to pass proglottids containing eggs on pasture. If a person accidentally consumes a parasite egg, they become infected with coenurosis. The primary method of controlling coenurosis is the regular administration of canine anthelmintics and the proper disposal of sheep and goat brain.

Presence of IgG antibodies is not a reliable marker of Toxoplasma gondii infection in feral mice

The single-celled parasite Toxoplasma gondii uses mice as a vector to reach its definitive host, the cat, where it can accomplish its sexual reproduction and produce oocysts, which will contaminate the environment. In this study, we have captured 103 feral house mice (Mus musculus) on Kangaroo Island, Australia. We have measured the level of exposure to T.gondii serologically with the Modified Agglutination Test and conjointly with a T.gondii B1 gene PCR. We have included stringent quality control steps in the molecular analysis to reduce the risk of false positivity and false negativity. Our results indicated a low seroprevalence of 0.97%, 95%CI [-0.36; 0.58] associated with the detection of T.gondii genetic material in 51.46%, 95%CI [41.93, 60.88] of mice brains. Neither sex nor mice body weight had an effect on the PCR outcome. We postulate that both the transmission route, horizontal or vertical, and natural selection processes could lead to this discordance which has been observed elsewhere in wild mice. The question of the biological mechanisms allowing the chronic infection of wild mice in the absence of a measurable humoral immune response remains. Our findings indicate that serological studies should not be used to measure the level of exposure to T.gondii in feral house mice.

One health approach to toxocariasis in Brazilian indigenous populations, their dogs, and soil contamination.

Although socioeconomic vulnerability and lifestyle factors may contribute to the transmission of Toxocara spp., no study has investigated indigenous populations in Brazil using the One Health approach. Accordingly, this study assessed anti-Toxocara spp. antibodies in Brazilian indigenous people and healthcare professionals by enzyme-linked immunosorbent assay. Presence of Toxocara spp. eggs (feces and hair) in dogs as definitive hosts and in soil samples of the indigenous communities were also recovered and molecularly investigated. Overall, 342/463 (73.9%) indigenous individuals and 46/147 (31.3%) non-indigenous healthcare professionals were seropositive for Toxocara spp. In addition, T. canis eggs were retrieved from 9/194 (4.6%) dog fecal samples and 4/204 (2.0%) dog hair samples, mainly from the Paraná State communities (3/42; 7.1%). Soil contamination was observed only in the Paraná State communities (36/90; 40.0%), with the molecular detection of T. canis. River water consumption was also associated with indigenous seropositivity (Odds ratio, 11.4). Indigenous individuals in Paraná State communities were 2.72-fold more likely to be seropositive than those in São Paulo State, likely due to a lack of sanitary infrastructure. In this scenario, a primarily soil-transmitted disease may also have become waterborne, with embryonated eggs probably spread to water supplies by rain. Full-time healthcare professionals in daily contact with indigenous communities were 9.2-fold more likely to be seropositive than professionals who visited sporadically, suggesting exposure to Toxocara spp. during their work and raising health concerns. In addition, the findings herein showed a significantly higher seroprevalence in indigenous people than in healthcare workers (χ2 = 85.5; p < 0.0001), likely due to overtime exposure to Toxocara spp. In conclusion, Brazilian indigenous communities are highly exposed to toxocariasis, with poor infrastructure and contact with contaminated river water as associated risk factors and a higher risk of infection in healthcare professionals working full-time in these communities.

Nasal vaccination of six squirrel monkeys (Saimiri sciureus): Improved immunization protocol against Toxoplasma gondii with a nanoparticle-born vaccine

Toxoplasma gondii is an intracellular protozoon found worldwide, which completes its life cycle between felids (its definitive host) and other warm-blooded animals. While the infection rarely leads to severe complications in humans, many animal species are very susceptible to this infection, for example the squirrel monkey (Saimiri sciureus) which is the subject of this study. Toxoplasmosis is lethal for 80% of cases in this species, and fatal outbreaks are frequently reported in zoological parks.No efficient treatment exists, but a new vaccine prepared with maltodextrin nanoparticles containing killed T. gondii antigens has been tested recently in French zoos. The animals were immunized through heterologous administrations, with two nasal doses at one-month interval, followed by nasal/subcutaneous boosts thereafter. No death has been reported since the beginning of this vaccination campaign, but we felt the protocol could be simplified.Here, an improved and less-invasive immunization protocol was evaluated on 6 Saimiri sciureus in the French zoo La Palmyre. It consisted of two nasal administrations at one-month interval, followed by a nasal boost at 6 months. A specific memory T-cell immunity was observed by ELISPOT after two administrations in all the animals, without humoral responses. The results suggest that 2 nasal administrations induce a protective immune response against T. gondii infection and might be sufficient to induce a strong Tcell memory, further improving immunity.

Occurrence and prevalence of third-stage larvae of the Anisakidae family in Macrouridae species captured from bathyal depths of Sagami Bay, Japan

Anisakiasis is the prevailing form of foodborne illness in Japan, with Anisakidae larvae, specifically Anisakis simplex sensu stricto, serving as its causative agents. These larvae are commonly found in mackerel, sardines, and skipjacks retailed at fresh fish establishments. While the infection rates of Anisakidae larvae in these surface-dwelling fish have been extensively studied, their prevalence in deep-sea fish species remains inadequately understood. This investigation aims to determine the infection rates of Anisakidae larvae in three Macrouridae species—namely Coryphaenoides acrolepis, Coelorinchus japonicus, and Coelorinchus macrochir—which represent the most significant inhabitants of the deep-sea realm. Employing artificial digestion techniques, we successfully retrieved all internal contents of the fish, including the nematode larvae. Some Anisakidae larvae were morphologically identified as A. simplex sensu lato and further identified to species by PCR-RFLP analysis. Two larvae showed a band pattern that appeared to be a hybrid between A. simplex sensu stricto and A. berlandi, which after sequence analysis was considered to be an intraspecific variation of A. berlandi. On the other hand, species considered to be unknown were sequenced and phylogenetic analysis was carried out along with identified larvae. The findings indicate that A. simplex sensu stricto was notably more abundant in C. acrolepis, obtained at a depth of 1000 m. In C. japonicus and C. macrochir, captured at a depth of 400 m, a considerable number of Skrjabinisakis paggiae and Pseudoterranova ceticola, were detected in the deep-sea dwelling Kogia breviceps and K. sima as definitive hosts, were detected. Notably, a single C. macrochir harbored seven species of Anisakidae larvae, with an infection tally of nearly 200 individuals of S. paggiae. Thus, a substantial prevalence of Anisakidae larvae in the deep-sea-dwelling Macrouridae species potentially plays a significant role in the transmission pathway to cetaceans as their final hosts.

Prevalence of Angiostrongylus cantonensis in definitive and intermediate hosts collected from agricultural areas in Ampayon, Butuan City, Southern Philippines.

Angiostrongyliasis is a parasitic disease and a leading cause of human eosinophilic meningoencephalitis caused by rat lungwormAngiostrongylus cantonensis. This parasite infects a wide range of animal hosts, including snails and rats, which plays a significant role in zoonotic transmission. The study was conducted to determine the prevalence ofA.cantonensisinfection in freshwater snails and definitive rat hosts in the agricultural area in Ampayon, Butuan City, Philippines. A total of 54 rat samples and 719 snail individuals were collected in June and July 2020. An overall 2.36% prevalence rate ofA. cantonensissnail infection was recorded, consisting of Pomacea canaliculataandMelanoides tuberculata, with a prevalence rate of 4.05% and 1.38%, respectively. Results revealed an overall prevalence of 38.9% in rat infection.Rattus tanezumi(48.48%) showed a higher infection thanRattus norvegicus(23.80%). Higher infection rates were found in rice field environments than residential houses, with 44.12% and 30% prevalence rates, respectively. Moreover, male rats showed higher infection rates (50%) than female rats (26.92%). Among age classes, adult rats had significantly higher infection rates (48.57%) than juvenile rats (21.05%). Correlation analysis showed a significant positive correlation betweenA. cantonensisinfection intensity to the body length (r = 0.603; p = 0.001) and body weight (r = 0.715; p = 0.000) of rats. The study exemplifies the critical role of intermediate and definitive hosts for angiostrongyliasis. Infected freshwater snails and rats in rice fields make these agricultural areas a venue forA. cantonensisemergence. Integrated actions, health education campaigns, surveillance, hygiene, and good farming practices will help prevent the potential risk of the transmission of angiostrongyliasis in the area.

Sarcocystis sp. shed by the common boa snake (Boa constrictor) in Brazil

The genus Sarcocystis contains around 200 species and 25 of these infect snakes. Two Sarcocystis spp. shed by snakes have called special attention of the scientific community. S. nesbitti, which is shed by scrub pythons (Simalia amethistina), causes myopathy in humans that consume water or food contaminated with the parasite. Sporocysts of S. singaporensis, excreted by reticulated pythons (Malayopython reticulatus), is letal for rats and was successfully tested in the biological control of these rodents. A high biodiversity of snakes is found in Brazil, however, scarce information is available about Sarcocystis spp. in Brazilian snakes. Herein, we investigated Sarcocystis sp. in feces of the common boa (Boa constrictor) from Salvador, as it is widely distributed in Brazil and it is also bred in other countries. Feces of 65 boas were examined, and Sarcocystis sp. was found in 1/65 (1.53%) snakes. All snakes were alive, and for this reason, intestinal scrapping, which is the most sensitive method to detect the parasite, was not performed. Morphometric evaluation of sporocysts showed significant differences in their sizes. PCR and multilocus sequencing of four genetic markers (cox1, 18S, ITS1, and 28S) revealed that sporocysts corresponded to a new Sarcocystis species. Sequences of cox1 and 18S had identities of 100% and higher than 98%, respectively, with sequences obtained from the rodent Lagostomus maximus in Argentina. ITS1 and 28S sequences did not match with any known Sarcocystis sp. No ITS1 and 28S sequences were available for the Sarcocystis sp. found in the Argentinian L.maximus. Bioassay using the boa sporocysts was conducted in three mouse lineages and in Rattus norvegicus, but no parasitic stages were detected in these rodents. We concluded that the common boa is probably the definitive host of a new species of Sarcocystis sp. that has L. maximus or related rodents as intermediate hosts.

Human infections by the rat tapeworm Hymenolepis diminuta in China.

The rat tapeworm Hymenolepis diminuta is a parasite that usually uses rats as a definitive host. It also infects humans and non-human primates. Human infections have been reported in 80 countries worldwide, including China. Nevertheless, nearly all the literature on human infections in China by the rat tapeworm is in Chinese journals, which are very difficult to access by readers outside China. The main aim of the current manuscript was to systematically review human infections by the rat tapeworm in China for readers inside and outside the country. Chinese characters for H. diminuta were used to search several databases, including Google Scholar. In total, 511 infections were reported in 24 Chinese provinces/autonomous regions, which surpassed 320 in Costa Rica as the country with the highest number of infections. Furthermore, three nationwide surveys on parasitic infections in the past 3 decades revealed detailed prevalence of this parasite along with that of roundworm, whipworm, hookworm and pinworm in Chinese populations. These data contribute to better understanding of this greatly neglected zoonosis in the world's most populated country.

Age-dependent relationships among diet, body condition, and Echinococcus multilocularis infection in urban coyotes.

Urban coyotes (Canis latrans) in North America increasingly exhibit a high prevalence of Echinococcus multilocularis, a cestode of recent and rising public health concern that uses rodents as intermediate hosts and canids as definitive hosts. However, little is known about the factors that drive the high urban prevalence of this parasite. We hypothesized that the diet of urban coyotes may contribute to their higher E. multilocularis infection prevalence via either (a) greater exposure to the parasite from increased rodent consumption or (b) increased susceptibility to infection due to the negative health effects of consuming anthropogenic food. We tested these hypotheses by comparing the presence and intensity of E. multilocularis infection to physiological data (age, sex, body condition, and spleen mass), short-term diet (stomach contents), and long-term diet (δ13C and δ15N stable isotopes) in 112 coyote carcasses collected for reasons other than this study from Edmonton, Alberta and the surrounding area. Overall, the best predictor of infection status in this population was young age, where the likelihood of infection decreased with age in rural coyotes but not urban ones. Neither short- nor long-term measures of diet could predict infection across our entire sample, but we found support for our initial hypotheses in young, urban coyotes: both rodent and anthropogenic food consumption effectively predicted E. multilocularis infection in this population. The effects of these predictors were more variable in rural coyotes and older coyotes. We suggest that limiting coyote access to areas in which anthropogenic food and rodent habitat overlap (e.g., compost piles or garbage sites) may effectively reduce the risk of infection, deposition, and transmission of this emerging zoonotic parasite in urban areas.

The same genotype of Sarcocystis neurona responsible for mass mortality in marine mammals induced a clinical outbreak in raccoons (Procyon lotor) 10 years later

Here, we report the first known outbreak of clinical protozoal myeloencephalitis in naturally infected raccoons by the parasite Sarcocystis neurona. The North American opossum (Didelphis virginiana) and the South American opossum (Didelphis albiventris) are its known definitive hosts. Several other animal species are its intermediate or aberrant hosts. The raccoon (Procyon lotor) is considered the most important intermediate host for S. neurona in the USA. More than 50% of raccoons in the USA have sarcocysts in their muscles, however clinical sarcocystosis in raccoons is rare. In 2014, 38 free-living raccoons were found dead or moribund on the grounds of the Saint Louis Zoo, Missouri, USA. Moribund individuals were weak, lethargic, and mildly ataxic; several with oculo-nasal discharge. Seven raccoons were found dead and 31 were humanely euthanized. Postmortem examinations were conducted on nine raccoons. Neural lesions compatible with acute sarcocystosis were detected in eight raccoons. The predominant lesions were meningoencephalitis and perivascular mononuclear cells. Histologic evidence for the Canine Distemper Virus was found in one raccoon. Schizonts and merozoites were present in the encephalitic lesions of four raccoons. Mature sarcocysts were present within myocytes of five raccoons. In six raccoons, S. neurona schizonts and merozoites were confirmed by immunohistochemical staining with S. neurona-specific polyclonal antibodies. Viable S. neurona was isolated from the brains of two raccoons by bioassay in interferon gamma gene knockout mice and in cell cultures seeded directly with raccoon brain homogenate. Molecular characterization was based on raccoon no. 68. Molecular characterization based on multi-locus typing at five surface antigens (SnSAG1-5-6, SnSAG3 and SnSAG4) and the ITS-1 marker within the ssrRNA locus, using DNA isolated from bradyzoites released from sarcocysts in a naturally infected raccoon (no. 68), confirmed the presence of S. neurona antigen type I, the same genotype that caused a mass mortality event in which 40 southern sea otters stranded dead or dying within a 3 week period in April 2004 with S. neurona-associated disease. An expanded set of genotyping markers was next applied. This study reports the following new genotyping markers at 18S rRNA, 28S rRNA, COX1, ITS-1, RON1, RON2, GAPDH1, ROP20, SAG2, SnSRS21 and TUBA1 markers. The identity of Sarcocystis spp. infecting raccoons is discussed.

Comprehensive Review of Key Taenia Species and Taeniosis/ Cysticercosis Disease in Animals and Humans

This manuscript provides a comprehensive review of the Taenia genus, encompassing 44 reported species, and their impact on domestic and wild animals as well as humans. The review focuses on 10 important Taenia species and covers various aspects including their description, life cycle, epidemiology, clinical signs of taeniosis and cysticercosis, diagnosis, treatment, control, and prevention. While humans primarily serve as the definitive hosts for Taenia asiatica, T. saginata, and T. solium, they can also become intermediate/accidental hosts for larval forms (metacestodes) of Taenia crassiceps, T. multiceps, T. serialis, T. solium, and T. Taeniaeformis.