Antibodies to Sarcocystis in Malaysians

Unusual Site of Oral Sarcocystosis in the Tongue

Sarcocystis is an intracellular protozoan parasite that manifests as a sarcocyst within the muscle fibers of an intermediate host. Sarcocystis commonly affects animals; in fact, cases of sarcocystosis involving human hosts are rare and often undiagnosed. The two types of Sarcocystis species that may infect and utilize humans as a definitive host are S. hominis and S. suihominis, both of which predominantly involve the gastrointestinal system. The low prevalence of intestinal sarcocystosis among humans is rarely accompanied by symptoms, except for individuals who ingest large amounts of the parasite. This study presents an unusual case of tongue sarcocystosis, a site that has not been previously reported, that was treated successfully with oral Albendazole for two weeks.

Seroprevalence of Sarcocystis falcatula in Two Islands of Malaysia using Recombinant Surface Antigen 4

Sarcocystosis was diagnosed worldwide by serodiagnostic tests utilising the whole parasite, for which the protozoa were maintained in vitro are more costly. In this study, antigenicity of Sarcocystis falcatula recombinant protein (rSfSAG4) was investigated towards the local communities of Pangkor and Tioman Islands and its seroprevalence was surveyed in these islands. A total of 348 human sera were tested using rSfSAG4 by Western blot and ELISA. High prevalence of sarcocystosis was observed in Tioman Island (80.6%) than in Pangkor Island (50.0%) by Western blot. In ELISA, the seroprevalence observed in Tioman Island was 45.9%, whereas in Pangkor Island 63.0%. In other parasitic infections, the prevalence was 34.0% by Western blot and 46.0% by ELISA. In healthy control group, 7% by Western blot and 8% by ELISA showed positivity to rSfSAG4. It is suggested SfSAG4 is a candidate antigen to measure seroprevalence of sarcocystosis.

Seroprevalence of sarcocystosis in the local communities of Pangkor and Tioman Islands using recombinant surface antigens 3 (rSAG3) of Sarcocystis falcatula

OBJECTIVE

To investigate the seroprevalence of Sarcocystosis in the local communities of Pangkor and Tioman islands, Malaysia, by using antigenic recombinant surface antigens 2 and 3 from Sarcocystis falcatula (rSfSAG2 and rSfSAG3) as the target proteins via Western blot and ELISA assays.

METHODS

SfSAG2 and SfSAG3 genes were isolated from S. falcatula and expressed in Escherichia coli expression system. A total of 348 serum samples [volunteers from both islands (n = 100), non-Sarcocystis parasitic infections patients (n = 50) and healthy donors (n = 100)] were collected and tested with purified SfSAGs in Western blot and ELISA assays to measure the seroprevalence of human sarcocystosis.

RESULTS

None of the sera in this study reacted with rSfSAG2 by Western blot and ELISA. For rSfSAG3, relatively high prevalence of sarcocystosis was observed in Tioman Island (75.5%) than in Pangkor Island (34%) by Western blot. In ELISA, the different prevalence rate was observed between Tioman Island (43.8%) and Pangkor Island (37%). The prevalence rate in other parasitic infections (amoebiasis, cysticercosis, filariasis, malaria, toxocariasis and toxoplasmosis) was 30% by Western blot and 26% by ELISA. Only 8% (by Western blot) and 10% (by ELISA) of healthy donors showed reactivity towards rSfSAG3.

CONCLUSION

This is the first study reporting a seroprevalence of sarcocystosis in Pangkor and Tioman Islands, Malaysia. The combination of Western blot and ELISA is suitable to be used for serodiagnosis of sarcocystosis. With further evaluations, SfSAG3 can potentially be used to confirm infection, asymptomatic screening, surveillance and epidemiological studies.

Detection of sarcocystosis in goats in Malaysia by light microscopy, histology, and PCR

A number of methods have been used for the detection of the presence of microsarcocysts in animals, but little information exists on the value between the various methods. This study therefore examined for Sarcocystis spp. using three different methods in 105 samples of skeletal muscle collected from goats slaughtered in an abattoir in Selangor, Malaysia from January to February 2014. Three methods were used, direct light microscopy of squashed fresh muscle tissues; histological examination of fixed, sectioned, and hematoxylin and eosin (H&E)-stained samples of muscle; and molecular identification by polymerase chain reaction (PCR). Of the 105 tissue samples, 55 (52.38 %) were positive by light microscopy (LM), 46 (43.8 %) by histology, and 95 (90.48 %) by PCR. Only 29 (27.6 %) and 5 (4.76 %) samples were positive and negative, respectively, by all three methods. The cysts were elongated to a spindle shape with a mean size of 393.30 × 81.6 μm and containing banana-shaped bradyzoites of size 12.32 × 2.08 μm. The wall of the cyst was radially striated with a thickness of 2.83 μm. Samples were tested for the presence of Sarcocystis-specific 18S rRNA and were identified as Sarcocystis capracanis. Of the three methods used, the PCR test appears to be the most useful method for the diagnosis of sarcocystosis especially for species identification.

Neglected tropical diseases among two indigenous subtribes in peninsular Malaysia: highlighting differences and co-infection of helminthiasis and sarcocystosis

Soil-transmitted helminth (STH) infections have been documented among these minority groups since 1938. However the prevalence of STH is still high among these communities. Most studies tend to consider the Orang Asli (indigenous) as a homogenous group. In contrary, different subtribes have their own cultural practices. To understand this variation better, we studied the prevalence and associated factors of STH and other gut parasitic infections among two common subtribes (i.e. Temuan and Temiar). Results showed that the prevalence of the overall STH infections was higher in the Temuan subtribe (53.2% of 171) compared to the Temiar subtribe (52.7% of 98). Trichuris trichiura (46.2%) was the most prevalent parasite in the Temuan subtribe, followed by Ascaris spp. (25.7%) and hookworm (4.1%). In contrast, Ascaris spp. (39.8%) was more prevalent among the Temiar subtribe, preceded by T. trichiura (35.7%) and finally hookworm (8.3%). There were also co-infections of helminthiasis and intestinal protozoa among both Temuan and Temiar subtribes with rates being three times higher among the Temiar compared to Temuan. The most common co-infection was with Entamoeba histolytica/dispar/moshkovskii (n = 24; 24.5%, 16.0-33.0), followed by Giardia spp. (n = 3; 3.1%, -0.3-6.5). In Temuan, STH infection individuals were also infected with Entamoeba histolytica/dispar/moshkovskii (n = 11; 6.4%, 5.0-13.8), Cryptosporidium spp. (n = 3, 1.8%, -0.2-3.8) and Giardia spp. (n = 2, 1.2%, -0.4-2.8). In comparison, there was no Cryptosporidium spp. detected among the Temiar. However, it was interesting to note that there was an occurrence of co-infection of intestinal helminthiasis and sarcocystosis (intestinal) in a Temiar individual. The last report of sarcocystosis (muscular) among the Orang Asli was in 1978. The present study highlighted the importance of understanding the variation of infections amongst the different Orang Asli subtribes. It is vital to note these differences and use this knowledge to customise effective control measures for the various subtribes.

Current status of epidemiology and diagnosis of human sarcocystosis

Species of Sarcocystis are Apicomplexan parasites requiring intermediate and definitive hosts to complete their life cycle. Humans are one of many natural host species and may serve as both intermediate and definitive hosts. However, the extent and public health significance of human Sarcocystis infection are incompletely known. In this minireview, we provide an update on the epidemiology and diagnosis of human sarcocystosis and propose some tools that could contribute to a better understanding of the clinical significance and epidemiology of Sarcocystis infections.

Sarcocystis nesbitti infection in human skeletal muscle: possible transmission from snakes

Sarcocystis nesbitti is an intracellular protozoan parasite found as sarcocysts within muscle fibers of intermediate hosts (monkey and baboon). The definitive host is suspected to be the snake. We report two cases from a larger cohort of 89 patients who had fever, headache, and generalized myalgia after a trip to Pangkor Island, Malaysia. Sarcocysts were detected in skeletal muscle biopsy specimens by light and electron microscopy from these two patients. DNA sequencing based on the 18S ribosomal DNA region identified the Sarcocystis species as S. nesbitti. We also identified S. nesbitti sequences in the stools of a snake (Naja naja). Phylogenetic analysis showed that these sequences form a cluster with most of the other known Sarcocystis species for which the snake is a definitive host. We believe these two patients were likely to have symptomatic acute muscular sarcocystosis after S. nesbitti infection that may have originated from snakes.

Genetic assemblage of Sarcocystis spp. in Malaysian snakes

Background

Sarcocystis species are protozoan parasites with a wide host range including snakes. Although there were several reports of Sarcocytis species in snakes, their distribution and prevalence are still not fully explored.

Methods

In this study, fecal specimens of several snake species in Malaysia were examined for the presence of Sarcocystis by PCR of 18S rDNA sequence. Microscopy examination of the fecal specimens for sporocysts was not carried as it was difficult to determine the species of the infecting Sarcocystis.

Results

Of the 28 snake fecal specimens, 7 were positive by PCR. BLASTn and phylogenetic analyses of the amplified 18S rDNA sequences revealed the snakes were infected with either S. nesbitti, S. singaporensis, S. zuoi or undefined Sarcocystis species.

Conclusion

This study is the first to report Sarcocystis infection in a cobra, and S. nesbitti in a reticulated python.

Polyparasitism is associated with increased disease severity in Toxoplasma gondii-infected marine sentinel species

In 1995, one of the largest outbreaks of human toxoplasmosis occurred in the Pacific Northwest region of North America. Genetic typing identified a novel Toxoplasma gondii strain linked to the outbreak, in which a wide spectrum of human disease was observed. For this globally-distributed, water-borne zoonosis, strain type is one variable influencing disease, but the inability of strain type to consistently explain variations in disease severity suggests that parasite genotype alone does not determine the outcome of infection. We investigated polyparasitism (infection with multiple parasite species) as a modulator of disease severity by examining the association of concomitant infection of T. gondii and the related parasite Sarcocystis neurona with protozoal disease in wild marine mammals from the Pacific Northwest. These hosts ostensibly serve as sentinels for the detection of terrestrial parasites implicated in water-borne epidemics of humans and wildlife in this endemic region. Marine mammals (151 stranded and 10 healthy individuals) sampled over 6 years were assessed for protozoal infection using multi-locus PCR-DNA sequencing directly from host tissues. Genetic analyses uncovered a high prevalence and diversity of protozoa, with 147/161 (91%) of our sampled population infected. From 2004 to 2009, the relative frequency of S. neurona infections increased dramatically, surpassing that of T. gondii. The majority of T. gondii infections were by genotypes bearing Type I lineage alleles, though strain genotype was not associated with disease severity. Significantly, polyparasitism with S. neurona and T. gondii was common (42%) and was associated with higher mortality and more severe protozoal encephalitis. Our finding of widespread polyparasitism among marine mammals indicates pervasive contamination of waterways by zoonotic agents. Furthermore, the significant association of concomitant infection with mortality and protozoal encephalitis identifies polyparasitism as an important factor contributing to disease severity in marine mammals.

Severity of toxoplasmosis, a water-borne zoonosis, varies widely from chronic and benign to acutely fatal. Here, we investigate polyparasitism (infection with multiple parasite species) as one factor governing the spectrum of disease in Toxoplasma gondii infections. This study utilized wild marine mammals as sentinels to detect contamination of waterways by T. gondii and a similar protozoan, Sarcocystis neurona, which have been linked to water-borne outbreaks in humans and wildlife along North America's Pacific Coast. Using genetic tools, we found high rates of protozoal infection, predominantly concomitant infections, in animals inhabiting major waterways of the Pacific Northwest. These dual infections of T. gondii and S. neurona were more frequently associated with mortality and protozoal encephalitis than single infections, indicating a role for polyparasitism in disease severity. Finally, rare T. gondii genotypes linked to a major human outbreak in the Pacific Northwest were abundant in marine mammals of the region, emphasizing wildlife as relevant sentinels for evaluation of human health risks. Our data implicate polyparasitism as a critical factor associated with the severity of protozoal disease. We also identify the need for vigilant surveillance of public waterways to prevent fecal contamination recurrently threatening human and wildlife health along the Pacific coast.

Sarcocystosis among wild captive and zoo animals in Malaysia

Sarcocystis sp. infection was investigated in 20 necropsied captive wild mammals and 20 birds in 2 petting zoos in Malaysia. The gross post-mortem lesions in mammals showed marbling of the liver with uniform congestion of the intestine, and for birds, there was atrophy of the sternal muscles with hemorrhage and edema of the lungs in 2 birds. Naked eye examination was used for detection of macroscopic sarcocysts, and muscle squash for microscopic type. Only microscopically visible cysts were detected in 8 animals and species identification was not possible. Histological examination of the sections of infected skeletal muscles showed more than 5 sarcocysts in each specimen. No leukocytic infiltration was seen in affected organs. The shape of the cysts was elongated or circular, and the mean size reached 254 x 24.5 µm and the thickness of the wall up to 2.5 µm. Two stages were recognized in the cysts, the peripheral metrocytes and large numbers of crescent shaped merozoites. Out of 40 animals examined, 3 mammals and 5 birds were positive (20%). The infection rate was 15% and 25% in mammals and birds, respectively. Regarding the organs, the infection rate was 50% in the skeletal muscles followed by tongue and heart (37.5%), diaphragm (25%), and esophagus (12.5%). Further ultrastructural studies are required to identify the species of Sarcocystis that infect captive wild animals and their possible role in zoonosis.

Sarcocystis spp. in human infections

Sarcocystis species are intracellular protozoan parasites with an intermediate-definitive host life cycle based on a prey-predator relationship. Asexual stages develop in intermediate hosts after they ingest the oocyst stage from definitive-host feces and terminate with the formation of intramuscular cysts (sarcocysts). Sarcocysts in meat eaten by a definitive host initiate sexual stages in the intestine that terminate in oocysts excreted in the feces. Most Sarcocystis species infect specific hosts or closely related host species. For example, humans and some primates are definitive hosts for Sarcocystis hominis and S. suihominis after eating raw meat from cattle and pigs, respectively. The prevalence of intestinal sarcocystosis in humans is low and is only rarely associated with illness, except in volunteers who ingest large numbers of sarcocysts. Cases of infection of humans as intermediate hosts, with intramuscular cysts, number less than 100 and are of unknown origin. The asexual stages, including sarcocysts, can stimulate a strong inflammatory response. Livestock have suffered acute debilitating infections, resulting in abortion and death or chronic infections with failure to grow or thrive. This review provides a summary of Sarcocystis biology, including its morphology, life cycle, host specificity, prevalence, diagnosis, treatment, and prevention strategies, for human and food animal infections.

Food-borne parasitoses in Malaysia epidemiological assessment and research needs

Food-borne parasitic zoonoses have emerged as a major public health problem in many countries and are posing a medical challenge. They are not only important from the economic point of view but also because of their severe sequelae. In Malaysia, these parasitoses are a tip of an iceberg problem. The article documents all the food-borne parasitic zoonoses reported in Malaysia. An epidemiological assessment of the diseases with research needs is highlighted.

High prevalence of human skeletal muscle sarcocystosis in south-east Asia

The prevalence of human skeletal muscle sarcocystosis in Malaysia was determined by serial examination of formalin-fixed, paraffin-embedded sections of tongue tissues obtained from consecutive, routine autopsies of subjects aged 12 years or more. Of 100 tongues examined, 21% were found to contain Sarcocystis; 66 cysts were found. The number of cysts per case varied from 1 to 13. In one case, 5 cysts were found in a single tissue section. The age range of positive cases was from 16 to 57 years (mean 37.7 years). Prevalence did not differ with regard to race, sex or occupation. The prevalence of human muscular sarcocystosis in our study was higher than that reported elsewhere. Preferential localization of Sarcocystis in tongue or head and neck and/or genuinely high prevalence in south-east Asia are possible explanations for this observation.