Identification of Sarcocystis spp. in wild boars (Sus scrofa) from Argentina

Sarcocystis spp. are intracellular protozoan parasites with an obligatory heteroxenous life cycle. The objective of this study is to identify Sarcocystis spp. in wild boar muscles from Argentina by light and transmission electron microscopy and molecular characterization. Muscle samples from diaphragm, tongue, masseter, intercostals, heart, and forelimbs of 240 wild boars were analyzed. Of the animals, 48.3% (116/240) were positive for sarcocysts by light microscopy, whereas 45.8% (110/240) were positive for Sarcocystis spp. by PCR targeting 18S rRNA fragment. These samples were subjected to a specific PCR for S. suihominis coxI gene, 3.6% (4/110) of which were weak positives. Unfortunately, sequence analysis was inconclusive. This could be related to a potentially low S. suihominis cyst load in the samples, or to an incomplete primer matching with the South American S. suihominis sequences. Seventeen individual sarcocysts were positive by PCR for the 18S rRNA fragment, whose sequences showed 99.75-100% identity with each other and with previously reported S. miescheriana sequences. A total of 21 cysts collected from 11 muscle samples and analyzed by TEM presented a cyst wall type compatible with S. miescheriana, and one cyst presented an ultrastructure compatible with S. suihominis. The latter came from a sample that also contained S. miescheriana cysts, indicating that the animal was co-infected. This is the first study that provides infection rates and describes and identifies morphological and molecular features of Sarcocystis spp. cysts in wild boars from South America.

Molecular identification of Sarcocystis species in diaphragm muscle tissue of European mouflon (Ovis gmelini musimon) from Austria

Previous morphological studies suggested that mouflon may have sarcocysts similar to those of sheep. However, to date, no molecular-based studies of the species of Sarcocystis infecting mouflon have been done. The present study identified Sarcocystis species in diaphragm muscle samples from 20 European mouflon (Ovis gmelini musimon). Molecular identification using the cox1 sequence analysis was performed on sarcocysts excised from muscle tissue and on DNA from digested muscle samples. Both frequency and intensity of infection in mouflon were high with 19 of 20 animals testing Sarcocystis positive and > 50 cysts per gram of tissue recovered from 10 of the 19 Sarcocystis positive animals. Molecular analysis revealed dominant Sarcocystis tenella (18/19 animals) and Sarcocystis arieticanis (1/19 animals), whose known intermediate hosts are sheep. In addition, Sarcocystis capracanis, which is known to form sarcocysts in goats, was detected in two animals. The results of this study demonstrated the digestion method to be superior over the direct isolation of sarcocysts for the molecular identification of Sarcocystis species in a certain host. Future research of Sarcocystis diversity in wild ovine and caprine species is needed.

Effects of Trichinella spiralis and its excretory/secretory products on autophagy of host muscle cells in vivo and in vitro

Trichinella spiralis (T. spiralis) is a widely distributed pathogenic microorganism that causes trichinellosis, a disease that has the potential of causing severe harm to their host. Numerous studies have demonstrated that autophagy can be triggered by microbial infection, such as bacteria, viruses, protozoa, and parasitic helminths. However, it’s still unknown whether autophagy can facilitate host resistance to T. spiralis infection. The present study examined the role of autophagy in striated muscle cell transformation following infection with T. spiralis in BALB/c mice. Transmission electron microscopy (TEM) was used to detect the production of the host diaphragm autophagosome after T. spiralis infection, and changes in the protein and transcriptional levels of autophagic marker proteins were also detected. The significance of autophagy in T. spiralis infection, namely inhibition of T. spiralis growth, was preliminarily evaluated by conducting in vivo experiments using autophagy inhibitors. Besides, we studied the effect of excretory-secretory products (ES) of T. spiralis on autophagy of C2C12 myoblasts. The changes in protein and gene expression levels in autophagy-related pathways in vitro and in vivo were measured as further evidence. The results showed that T. spiralis infection induced autophagy in the host muscle cells. Meanwhile, ES inhibited autophagy of myoblasts in vitro, but this did not affect the cell viability. The upregulation and downregulation of autophagy-related factors in skeletal muscle cells may indicate an adaptive mechanism providing a comfortable niche for the parasite.

Autophagy, a intracellular degradation system, is a kind of unique phenomenon in eukaryotic cells. The commonly referred autophagy is the process of forming autophagosomes by wrapping the cytoplasmic components with double-membrane structure, and then fusing with lysosomes to degrade the internal substances of the cell. Autophagy can be induced by various pathogens including parasites. When the body is infected with intracellular parasites, the host cell can remove the parasites by autophagy. However, parasites have also evolved defence mechanisms that use autophagy in host cells to promote growth. These can be seen in some intracellular parasitic infections such as Toxoplasma gondii and Plasmodium. Although the role of autophagy in other parasitic infections has been revealed, it remains unclear whether autophagy is involved in the invasion process by Trichinella. We investigated the role of Trichinella infection on host muscle cells autophagy and the effect of autophagosome formation on the survival of T. spiralis. Understanding the role of autophagy in the interaction between parasitic infection and host cell is of great significance for the prevention and treatment of Trichinella infection and the development of anti-parasite drugs.

Pathological and molecular identification of porcine cysticercosis in Maharashtra, India

Porcine cysticercosis, caused by metacestodes of Taenia solium is an important emerging zoonotic disease with public health and economic significance. Pigs acquire the disease through consumption of Taenia solium eggs excreted by human tapeworm carriers. The present study was conducted to investigate the prevalence of porcine cysticercosis in Nagpur and Mumbai region of Maharashtra, India by P/M examination of carcasses followed by histopathology of affected organs in infected animals and molecular identification of cysts for confirmation. Out of 1000 pigs examined during slaughter, three pigs were found to be heavily affected with T. solium cysts giving a prevalence of 0.3%. Histological section of brain in infected animals revealed marked vascular congestion of meninges, mild neuronal degeneration, perivascular cuffing and gliosis while the liver showed the infiltration of mononuclear cell, predominantly eosinophils throughout the parenchyma. Some degree of calcification was observed in the cysts lodged in liver while calcification was not evident in case of cysts lodged in brain, tongue, diaphragm and skeletal muscle. Molecular identification by PCR using two sets of oligonucleotide primers against LSU rRNA gene and Mt-Cox1 gene of T. solium confirms the cysts to be that of T. solium. The molecular diagnostics methods have been considered for validation in conjunction with P/M inspections, parasitological and histopathological examinations. The study confirms the presence of porcine cysticercosis in the two regions and demands proper sanitary measures to minimize the risk of infection from zoonoses and food safety point of view.

[The surgery of diaphragmatic hydatidosis and their complications]

Primary or secondary diaphragmatic echinococcosis is rare, accounting for 1% of the thoracic locations. They may be operative discovery or by their complication, hence a variable symptomatology making this localization a particular entity. The thoracic and abdominal CT allows a complete assessment. Surgery remains the only therapeutic approach. In complicated forms an additional surgery is required for complete care. The prognosis is generally good apart from the risk of recurrence. Through a series of 4 operated patients, we focus on the clinical and therapeutic features of this pathology and its complications.

Survey of Toxoplasma gondii antibodies in meat juice of wild boar (Sus scrofa) in several districts of the Czech Republic

INTRODUCTION AND OBJECTIVE

The aims of the study were: 1) to detect antibodies against Toxoplasma gondii from wild boar meat; 1) establish seroprevalence of toxoplasmosis in the wild boar population; 3) establish risk factors concerned in higher possible seroprevalence; 4) to estimate the usefulness of meat juice for detection of T. gondii antibodies in wild boar.

MATERIAL AND METHODS

Diaphragm meat juice samples from 656 wild boar (Sus scrofa) were collected during the hunting seasons between September 2008 - October 2010 from 9 districts of the Czech Republic. The samples were stratified per age category into 2 groups: piglets (n = 279) and yearlings together with adults (n = 377). The in-house ELISA test was used for the detection of antibodies against T. gondii from the meat juice samples.

RESULTS

Antibodies against T. gondii were detected by in-house ELISA in 260 of 656 wild boars (40%) with 26% prevalence in piglets (72/279) and 50% prevalence in yearlings and adults (188/377). The district total seroprevalences ranged between 32% - 59%, with a significantly higher prevalence in the district of Havlíčkův Brod (59%). Statistically significant differences (p-value < 0.05) were found between 2 age categories, and between 9 districts, with a significant variability in the district of Havlíčkův Brod. Seroprevalence correlated positively with farm density, but without any statistical significance.

CONCLUSION

The obtained results indicate that consumption of raw or undercooked meat from wild boars can carry an important risk of toxoplasma infection. Post mortem detection of antibodies in meat juice samples using ELISA is a useful alternative to blood serum examination. In addition, a diaphragm sample has been well-proven as a matrix sample for the contemporaneous diagnostics of trichinellosis and toxoplasmosis.

Molecular identification of Sarcocystis hominis in native cattle of central Iran: a case report

Sarcocystis spp. are two-host protozoan parasites belonging to the phylum Apicomplexa. Among different known species of Sarcocystis in cattle, only Sarcocystis hominis is important from the public health viewpoint, because of its zoonotic characteristics. This study presents the first molecular identification of S. hominis in native cattle in central Iran. A sample of diaphragm muscle from a 6-year-old native cow slaughtered at Yazd Slaughterhouse, Yazd, central Iran, was collected in May 2013. DNA extraction was performed, using the salting-out method. DNA purification and precipitation were performed consecutively. The amplicon and digestion results were analyzed using agarose gel electrophoresis. A PCR product with 926 bp in length was obtained after amplification, and 376 bp and 550 bp in length after digestion that identified S. hominis. To the best of our knowledge, this study is the first of its kind to be reported from Iran.

Porcine and rodent infection withTrichinella, in the Sierra Grande area of Río Negro province, Argentina

In 2000, two cases of human trichinellosis were detected in the Sierra Grande area of Rio Negro province, Argentina. As part of an investigation of the aetiology of these cases, 300 pigs slaughtered for consumption in the area between 2000 and 2002 were checked for Trichinella infection, by artificial digestion of a muscle sample. Twelve (5.6%) - four (7.3%) of the 55 checked in 2000, five (4.8%) of the 105 investigated in 2001, and three (2.1%) of the 140 investigated in 2002 - were found infected. Blood samples were collected from other pigs aged > 6 months old, so that sera could be tested, in ELISA and by western blotting, for anti- Trichinella antibodies. Of the 181 animals checked in the initial serological survey, 36 (19.9%) were found seropositive for Trichinella. When 35 of the seronegative pigs were re-checked 6 months later, three (8.6%) were found to have seroconverted. Four (15.4%) of 26 local rodents, caught in Sherman-type traps, were also found positive when checked for infection by artificial digestion. It appears that about 20% of pigs in the study area are infected each year, this high level of transmission being sustained by a high prevalence of infection in the local rodent populations.

[Sarcocystis cruzi (Protozoa: Apicomplexa: Sarcocystiidae) infection in european bison (Bison bonasus) from Białowieza Forest, Poland]

Samples of oesophagus, diaphragm and heart muscles were taken from one European bison from Białowieza Forest during seasonal European bison elimination in 2008. Five gram of each muscle was examined by staining small samples in 0.2% aqueous solution of methylene blue. After that they were placed between compressor glasses and examined under a dissecting microscope in order to detect Sarcocystis sp. infection. All sarcocysts observed were counted. The 5-g sample of the heart muscle yielded a total of 756 sarcocysts while that of the diaphragm contained 107 of them and that of the oesophagus--89. All of the sarcocysts were isolated from 1 g of each muscle by using preparation needles (probes). After that the sarcocysts were taken to 0.5% physiological solution and examined under light microscope. The special attention was paid to detection of their cyst wall, which was thin (1 microm up to 1.2 microm) and smooth in all cases. Sometimes villar protrusions were seen on the surface of the cysts. Differences between the size of sarcocysts isolated from different muscle samples were observed. The longest and the slenderest sarcocysts were found in the diaphragm. Slightly smaller in the oesophagus and the smallest ones in the heart muscle tissue. The average size of sarcocysts isolated from diaphragm was 957.6 microm x 112.7 microm. Sarcocysts found in the oesophagus measured 484.1 microm x 194.6 microm and those isolated from the heart muscle attained 305.4 microm x 103.9 microm. All of the sarcocysts isolated from heart, oesophagus and diaphragm muscles were identified Sarcocystis cruzi.

Concurrent infection with Trichinella spiralis and other helminths in pigs

The aim of this study was to investigate possible influence of different helmintosis in the development of Trichinella spiralis in experimental infected pigs. Forty-two Iberian pigs were allocated to six groups. Three groups were single inoculated with Ascaris suum, Metastrongylus apri or T. spiralis, respectively. Two groups were co-infected with T. spiralis and A. suum or T. spiralis and M. apri, respectively, while the last group included uninfected control pigs. Clinical signs were only observed in pigs with single or concurrent M. apri infections, with more severe respiratory symptoms in pigs with mixed M. apri infection. The number of A. suum and M. apri lung larvae, intestinal larvae of A. suum and adult M. apri were reduced in pigs with mixed Trichinella infections compared to pigs with single infections. In contrast, the number of liver white spots was higher in pigs with mixed infections. While T. spiralis muscular larval burdens were increased in pigs concomitantly infected with M. apri, they were reduced in pigs concomitantly infected with A. suum, compared to pigs receiving single infections with either of these helminths. Pigs with single or mixed A. suum infections showed higher eosinophil levels compared to the remaining groups. IgGt, IgG1, IgG2 and IgM against T. spiralis antigen could not be detected in pigs with single Ascaris or Metastrongylus infections, indicating that no cross-antibodies were produced. IgGt, IgG1 and IgM antibodies were detected earlier and generally at higher levels in mixed T. spiralis infections compared to single T. spiralis infections. The results suggest that T. spiralis had a low synergistic interaction with M. apri in concomitantly infected pigs, and an antagonistic interaction in concurrent infection with A. suum.

Application of Giemsa stain for easy detection of Trichinella spiralis muscle larvae

The application of Giemsa technique to stain compressed diaphragm samples obtained from rodents experimentally infected with Trichinella spiralis is described. Diaphragm samples from rats heavily infected with 20 muscle larvae per gram of body weight (20 ML/gbw) were cut into several pieces and stained with Giemsa; on the other hand, whole diaphragms from slightly infected mice (1 ML/gbw) were also stained with Giemsa. Besides, muscle samples were also stained with Giemsa. Observation at 10 x magnification revealed that both ML and nurse cells (NC) look as bluish structures clearly contrasting with the pinkish color of the non-infected muscle fibers. NC in the diaphragms of mice could be easily observed at naked eye as blue points contrasting with the pink surrounding areas formed by the non-infected muscle fibers. Among NC observed in the diaphragms of rats infected with 20 ML/gbw, 4.4% was multiple infection. These findings were confirmed in sectioned and hematoxylin-eosin stained specimens. This data could be usefulness for a rapid diagnosis of trichinellosis in post-mortem mammals without magnification procedures.

[The prevalence of Sarcocystis species in sheep slaughtered in municipality slaughterhouse in Kirikkale]

This study was undertaken for the determination of Sarcocysts species in sheep slaughtered in Kirikkale Municipality Slaughterhouse. For this study, oesophageal, diaphragm and intercostal muscles were collected from randomly selected 112 sheep out of 1131 sheep (814 sheep and 317 lambs) that were slaughtered from October 2005 to May 2006. The samples were examined for macro and microcyst of Sarcocysts spp. Macrocysts and microcysts were found in 58.92% of the overall samples. Microcysts were found in 47.32% and macrocysts were perceived in 20.53% of the sheep that were under examination. The distribution of the microcysts with respective to the age of the sheep was studied and it has been observed that 16.12% (5 in every 31 lambs) of the lambs under 1 year old and 59.25% (48 in every 81 sheep) of the sheep equal or older than 1 year old had possessed microcysts. Sarcocystis ovicanis (47.32%) and S. arieticanis (1.23%) were the species with the highest and lowest number of recurrences respectively. Macrocysts were observed in every sheep over one age. In addition, randomly selected oesophagi with macrocyst were examined histopathologically. Sarcocystis sporocysts were not found in dog feces.

Trichinella pseudospiralis from a wild pig in Texas

In December 2001, the routine inspection of a wild boar intended for human consumption revealed the presence of Trichinella ssp. larvae. Biological, morphological and genetic analyses demonstrated the parasite to be Trichinella pseudospiralis. This is the second report of T. pseudospiralis in the United States and the first report of the parasite in a food animal species in the U.S.

First isolation of Trichinella britovi from a wild boar (Sus scrofa) in Belgium

Since 1992, when the European Union Council Directive requires that wild boars (Sus scrofa) hunted in EU for commercial purpose should be examined for Trichinella, the infection has not been detected in wild boars from Belgium, despite serological evidence of the presence of anti-Trichinella antibodies in wildlife and previous reports of Trichinella larvae in this host species. In November 2004, Trichinella larvae were detected in a wild boar hunted near Mettet, Namur province (Southern Belgium). Larvae were identified as Trichinella britovi by polymerase chain reaction methods. This is the first report of the identification of Trichinella larvae from Belgium at the species level. The detection of T. britovi in wildlife in Belgium is consistent with findings of this parasite in other European countries and confirms the need to test game meat for Trichinella to prevent its transmission to humans.

Toxoplasmosis in a Hawaiian monk seal (Monachus schauinslandi)

Toxoplasma gondii infection in marine mammals is intriguing and indicative of contamination of the ocean environment with oocysts. T. gondii was identified in a Hawaiian monk seal (Monachus schauinslandi) that had visceral and cerebral lesions. Tachyzoites were found in the lymph nodes, spleen, diaphragm, heart, adrenal glands, and brain. A few tissue cysts were found in sections of the cerebrum. The diagnosis was confirmed serologically, by immunohistochemical staining with T. gondii-specific polyclonal rabbit serum, and by the detection of T. gondii DNA. The genotype was determined to be type III by restriction fragment length polymorphisms of the SAG2 gene. This is the first report of T. gondii infection in a Hawaiian monk seal.

Seasonal variation in Sarcocystis species infections in goats in northern Iraq

We investigated the prevalence of sarcocystosis in 826 goats slaughtered in the winter season from November to April in northern Iraq. The prevalence of macrocysts was on average 34%, with only 20% infected animals in November, but 46% in February. The infection rate in 1-, 3- and 6-year-old goats was 4%, 48%, and 83%, respectively. The highest specificity of infection was in the oesophagus (99%) and the lowest in the diaphragm (3%). Grossly, we identified 2 forms of macroscopic sarcocysts, fat and thin, with different morphological characteristics. The prevalence of microcysts was 97% and no effects of age, sex and seasonal variations were observed. Development of microcysts in the small intestine of dogs and cats has also been investigated. The pre-patent period in experimentally infected dogs was 12–14 days and the patent period lasted 64–66 days. A dog shed about 155 million sporocysts, but no sporocysts were shed by cats that had been fed the same infected tissues, thus identifying the microcysts as Sarcocystis capracanis.

Immunization with Trichinella spiralis Korean isolate larval excretory-secretory antigen induces protection and lymphocyte subset changes in rats

Protection and immune responses were studied in rats immunized with Trichinella spiralis muscle stage larval excretory-secretory antigen (ES Ag) without adjuvant. Protection was assessed by the degree of adult worm burden and the yield of muscle (diaphragmatic) larvae after challenge infection with live larvae. Lymphocyte subsets were identified by flow cytometry in the spleen and peripheral blood. Cytokine production and specific IgG, IgG1 and IgG2a antibody responses were measured. Immunization with ES Ag produced highly significant protection against adult stages (98.4%) and muscle larvae (82.9%). Th2 type cytokines (IL-10, IL-4) were predominant. Anti-muscle stage larval ES Ag antibody was significantly elevated in the order IgG2a > IgG1 > IgG on the 2nd day after final immunization and on the 7th day after challenge infection. Expression of CD4+ and the CD4+/CD8+ ratio from spleen and blood were significantly increased compared to the control. These results demonstrate that immunization with T. spiralis antigen can elicit robust immune response, resulting in complete protection against infective larvae, and this protection can be achieved without the use of any adjuvant.

Skeletal muscle regeneration and Trypanosoma cruzi-induced myositis in rats

Although Chagas' disease is known to provoke severe acute myositis, information on muscle regeneration is missing. The current paper shows that during T. cruzi infection in rats, skeletal muscle parasitism and the consequent inflammatory process are higher in muscle with a high proportion of type-I myofibres (soleus and diaphragm). Immunohistochemistry showed an acute inflammatory process characterized by ED1+ and ED2+ macrophages, CD8+ lymphocytes, and NK cells. Parasite-nest rupture provoked segmental degeneration of myofibres followed by regeneration. These phenomena were observed at both light and transmission electron microscopy levels. Myofibre regeneration involved activation of satellite cells assessed by the expression of MyoD, a muscle-specific transcription factor. Ultrastructural evidence of fusion of myoblast-like cells with the intact segment of degenerating fibres has been provided. At the chronic phase no signs of fibrosis were found, but sparse and small inflammatory foci were found. Our results argue against the relevant participation of autoimmunity phenomena in both acute and chronic phases and furnish a new view for explaining histopathological findings in human patient muscles.

[Uncommon abdominal sites of hydatid disease. Our experience with the surgical treatment of 15 cases]

The aim of this retrospective study is to report on a series of 15 patients with abdominal hydatid disease in uncommon sites submitted to surgery in our unit over the period 1974-2003. Eight women and 7 men (mean age: 48.4 years) were included in the study. The hydatid cysts were located in the peritoneum in 8 patients, in the spleen in 5, in the kidney in 1 and in the retroperitoneum in 1. In 4 cases the peritoneal cysts were solitary, while 4 patients in this subgroup presented multiple cysts and 2 had concomitant liver hydatidosis. The splenic cysts were solitary in 2 cases, associated with a hepatic cyst in 2 and with a lung cyst in 1. The renal and retroperitoneal cysts were both solitary. The diagnosis was made at operation in 3 cases, while in 12 patients it was made by serological tests, ultrasonography and/or CT. All patients were operated on: we performed a total cystectomy in 7 patients with peritoneal cysts and in the patient with a retroperitoneal location, splenectomy in the 5 splenic cysts and a partial cystectomy with external drainage of the residual cavity in 1 peritoneal cyst and in the renal location. The postoperative course was regular with no mortality and no major morbidity in 14 patients, while 1 patient submitted to splenectomy developed a subphrenic abscess that required surgical drainage. Two recurrences occurred in patients with peritoneal cysts 71 and 20 months, respectively, after the first operation and these were managed by total cystectomy. The diagnosis of uncommon abdominal sites of hydatid disease is more accurate today because of the new imaging techniques, which are often able to show specific radiological signs of hydatid disease. The treatment of choice is surgical and complete removal of the cyst is the gold standard, but its feasibility is related to the location of the cyst.

Trypanosoma cruzi: mixture of two populations can modify virulence and tissue tropism in rat

In rats, CL-Brener clone caused high mortality, severe acute myocarditis, and myositis that subsided completely in surviving animals. Accordingly, no parasite kDNA could be amplified in several organs after 4 months. The monoclonal JG strain caused null mortality, acute predominantly focal myocarditis, discrete and focal myositis, and a chronic phase with sparse inflammatory foci. Double infection with both Trypanosoma cruzi populations turned mortality very low or null. At the end of the acute phase, the heart exhibited only JG strain kDNA (LSSP-PCR), while skeletal muscles and rectum exhibited only CL-Brener kDNA. Molecular and histopathological findings were accordant. In double infection chronic phase, JG strain remains in heart and appeared in organs previously parasitized by CL-Brener clone. Understanding the virulence and histotropism shifts now described could be important to clarify the variable clinical course and epidemiological peculiarities of Chagas' disease.

Evaluation of a digestion assay and determination of sample size and tissue for the reliable detection of Trichinella larvae in walrus meat

A digestion assay was validated for the detection of Trichinella larvae in walrus (Odobenus rosmarus) meat, and appropriate samples for testing were determined using tissues from infected walruses harvested for food. Examination of muscles from 3 walruses showed that the tongue consistently contained approximately 2-6 times more larvae than the pectoral and intercostal muscles. Comparison of numbers of larvae in the root, body, and apex of the tongue from 3 walruses failed to identify a predilection site within the tongue, but the apex was considered an optimal tissue because of the high larval density within the tongue and the ease of collection. All 31 spiked samples weighing 50 g each and containing between 0.1 and 0.4 larvae per gram (lpg) were correctly identified as infected, indicating that the sensitivity of this procedure is adequate for diagnostic use. A sample size of 10 g consistently detected larvae in 2 walrus tongues containing > or = 0.3 lpg (n = 40), and until additional data are available, sample sizes from individual walrus tongues should be a minimum of 10 g. This study provides the preliminary data that were used for the development of a food safety analytical protocol for the detection of Trichinella in walrus meat in arctic communities.

Prevalence of Sarcocystis infection in horses in Mongolia

Sarcocystis infection was detected in 93% of horses in Mongolia. Using the compress method, sarcocysts were found in the muscles of the diaphragm, heart and tongue in 40 of the 43 horses that were slaughtered at the Makh Impex Meat Company in Ulaan Baatar in July 1998. The muscle of the tongue showed the highest rate (97.5%) of infection. The distribution of sarcocysts in the muscles was positively correlated with horse age; the rate of detection was significantly lower (p=0.01) in the under 10 year old group than the older group. All horses were apparently healthy and were slaughtered for human consumption.

Trypanosoma cruzi: role of host genetic background in the differential tissue distribution of parasite clonal populations

Chagas' disease, caused by the protozoan parasite Trypanosoma cruzi, has quite a variable clinical presentation, ranging from asymptomatic to severe chronic cardiac and/or gastrointestinal disease. The reason for that is not completely understood, but both parasite and host genetic traits are certainly involved. Recently, we have demonstrated clinically and experimentally that the genetic variability of T. cruzi is one of the determinants of the pattern of tissue involvement in Chagas' disease. We then decided to turn our attention to the role of host genetic background. To study this, we compared the infection of four lineages of mice [three inbred (BALB/c, DBA-2, and c57Black/6) and one outbred (Swiss)] with two T. cruzi clonal populations, the Col1.7G2 clone and the JG monoclonal strain. The tissue distribution of T. cruzi strains was identical for BALB/c and DBA-2 mice, but very different in C57BL/6 (H-2(b)) and outbred Swiss mice. This result clearly demonstrates the importance of host genetic aspects in the process. Since BALB/c and DBA-2 have the same H-2 haplotype (H-2(d)) and C57BL/6 does not (H-2(b)), it is possible that MHC variability may be involved in influencing the tissue distribution of involvement in experimental Chagas' disease of the mouse.

Extraintestinal migration of Pharyngostomum cordatum metacercariae in experimental rodents

Extraintestinal migration patterns of Pharyngostomum cordatum (Digenea: Neodiplostomidae) were studied in experimental rodents such as mice, rats, and hamsters. When metacercariae isolated from grass snakes were infected orally to rodents, they penetrated the intestinal wall at days 2-3 post-infection (p.i.) and were discovered mainly in the diaphragm, intercostal muscles, and vital organ such as the lungs at days 7-28 p.i., without morphological changes. Interestingly, from several rodents which died suddenly at days 2-9 p.i., small to considerable numbers of metacercariae were found, not only in the lungs, but also in the heart and brain. Within the tissues, worms were freely motile until day 7 p.i., but later they were surrounded by host cells, and finally tissue cysts were formed. When metacercariae harvested from the snakes and intercostal muscles of rodents were infected orally to cats, they developed into adult flukes in the small intestine. The results show that P. cordatum undergoes considerable extraintestinal migration including the vital organs of its rodent hosts.

Sarcocystis miescheriana infection in domestic pigs (Sus scrofa) in the Philippines

Sarcocystis miescheriana sarcocysts were identified in skeletal muscles of 9 (27%) of 33 swine slaughtered for human consumption. Sarcocysts were 144-180 microm x 20-38 microm in size. Ultrastructurally, the cyst wall resembled the type 10 sarcocyst wall. The villar protrusions (VP) were 3-4.5 microm long and 0.6-1.2 microm wide and had prominent longitudinally arranged microtubules extending from the VP tips to the granular layer (=ground substance). The parasitophorous vacuolar membrane with its underlying electron-dense layer (EDL) measured 25 nm in thickness. The base of the VP exhibited minute (0.42-0.87 microm) bulblike inpocketings. Each VP had 80-90 microtubules situated underneath the EDL. The granular layer was 0.5-1.2 microm thick, and contained hairlike microtubules continuous with those of the VP core. This is the first report of S. miescheriana in Philippine domestic pigs Sus scrofa.

First report of Trichinella nativa in red foxes (Vulpes vulpes schrencki) from Otaru City, Hokkaido, Japan

Forty-three red foxes (Vulpes vulpes schrencki) and nine raccoon dogs (Nyctereutes procyonoides viverrinus) were captured in Otaru City, Hokkaido, Japan and examined by muscle digestion for the presence of Trichinella sp. larvae. Of the foxes, five (11.6%) were positive for larvae of Trichinella nativa while none of the raccoon dogs were found to be positive. This finding suggests that the red foxes are important reservoir hosts of sylvatic trichinellosis in Otaru, Hokkaido. This is the first report on Trichinella nativa in wild red foxes of Hokkaido, Japan.

Infectivity, predilection sites, and freeze tolerance of Trichinella spp. in experimentally infected sheep

A total of 36 sheep in groups of 4 were inoculated with 9 isolates of Trichinella and euthanized after 10 weeks. Thereafter, numbers of muscle larvae were determined in 13 different muscles/muscle groups. Muscle larvae were found in high numbers in all four sheep inoculated with T. spiralis, in lower numbers in two sheep inoculated with T. pseudospiralis (USA isolate), and in very low numbers in one sheep inoculated with T. pseudospiralis (USSR isolate) and one inoculated with T. britovi. In infections of high and moderate larval intensity, predilection sites of T. spiralis were the masseter muscles, the tongue, and the diaphragm and those of T. pseudospiralis were the masseter muscle and the neck. In low-intensity infections, muscle larvae were detected only in the diaphragm or in pooled muscle samples. For evaluation of the freeze tolerance of the different Trichinella species in sheep-muscle tissue, samples taken from the filet were stored at +5 degrees, -5 degrees, and -18 degrees C, respectively. After exposure for 1 and 4 weeks the tissue was digested and the released larvae were inoculated into mice for determination of the reproductive capacity index (RCI). Larvae of both T. spiralis and T. pseudospiralis survived freezing at -5 degrees and -18 degrees C for 4 weeks.

Growth performance, meat quality and activities of glycolytic enzymes in the blood and muscle tissue of calves infected with Sarcocystis cruzi

Growth performance and the pattern of glycolytic enzymes in the blood plasma were assessed during experimental Sarcocystis cruzi infection (1 x 10(5) sporocysts per calf) in six calves; five calves served as noninfected controls. At slaughter (68 or 88 days post infection), carcass weight, dressing percentages and several parameters of meat quality (pH, color brightness, rigor, water absorbing capacity, water binding capacity) were recorded. Moreover, enzyme activities were measured in muscle homogenates. Weight gain was significantly impaired by the infection. Activities of lactate dehydrogenase (LDH) and aldolase (ALD) significantly increased in the blood plasma of the infected calves during the chronic stage of the disease, while glucose-6-phosphate dehydrogenase (G6PDH) and isocitrate dehydrogenase (ICDH) were not significantly altered. This was accompanied by a significant decrease of enzyme activities in the Musculus longissimus dorsi (LDH, ALD), in the diaphragmatic musculature (ALD, G6PDH) and in the heart (LDH, ALD). Activities of LDH, ALD, ICDH and G6PDH were visualized by enzyme histochemistry within the developing sarcosporidial cysts. However, isoenzymes of parasite origin could not be demonstrated by agar-gel electrophoresis of muscle homogenates or blood plasma. It is concluded that sarcocystiosis of even moderate severity alters the performance of calves but not meat quality. Leakage of glycolytic enzymes from the affected muscles is the probable cause of increased plasma enzyme activities. Although these enzymes are also synthesized by the parasite, the contribution of parasite-derived enzymes to the observed changes of enzyme patterns remains in question.

The hispid cotton rat (Sigmodon hispidus) as an experimental host for the bovine liver fluke (Fasciola hepatica)

The results of a study testing the susceptibility of the hispid cotton rat, Sigmodon hispidus, to infection with Fasciola hepatica are described. Ten cotton rats were placed into one of four test groups, one uninfected control or three animals each receiving two, five, or 10 F. hepatica metacercariae. Three of nine (33%) became infected, and two of these animals carried the infection to patency. At necropsy one animal had two mature F. hepatica within the common bile duct, and the other harbored a single fluke. Gross and microscopic changes, primarily of the liver, associated with infection are described, as are fecal egg counts throughout the duration of infection.

Sarcocystis levinei infection in Philippine water buffaloes (Bubalus bubalis)

Ultrastructural studies of sarcocysts obtained from Philippine water buffaloes revealed the presence of the commonly reported macroscopic species, Sarcocystis fusiformis, and the microscopic species Sarcocystis levinei (Dissanaike A, Kan S. Studies on Sarcocystis in Malaysia. I: Sarcocystis levinei n.sp. from the water buffalo Bubalus bubalis. Z Parasitenkd 1978;55:127-38), (Huong L, Dubey J, Uggla A. Redescription of Sarcocystis levinei Dissanaike and Kan, 1978 (Protozoa: Sarcocystidae) of the water buffalo (Bubalus bubalis). J Parasitol 1997;83:1148-52). The globular to oval microscopic cysts commonly observed in the muscles of the diaphragm and neck exhibit compartmentalized arrangement of zoites with septal partitions and measure 13-48 microns in diameter. The parasitophorous vacuolar membrane of sarcocyst bears minute and hair-like villar protrusions measuring 2.3-2.75 microns long emanating at certain distances from the primary cyst wall and lack microfilaments. Villar protrusions have expanded to dome-shaped base measuring 0.33-1.6 microns long by 0.22-1.0 micron wide, and intermediate and tapering distal segments bent approximately 90 degrees and run parallel to the cyst surface. The distal segments at some areas join to form conical tufts. The primary cyst wall bears numerous prominent undulations that are arranged in small clusters. The ground substance is 0.42-0.57 micron thick. This paper documents the first report of S. levinei in Philippine water buffaloes possessing the type 7 cyst wall.

Sarcocystis muris--a rare case in laboratory mice

In a lifespan transgeneration study under standard laboratory conditions using a total of 4682 CBA/J mice, unusual intramuscular inclusions were found in the diaphragm, heart and skeletal muscle of one mouse using light microscopy. Located within the myocytes, they caused no visible tissue reaction. Cross-sections of these spherical and cystic lesions showed numerous banana-shaped structures, identified as permanent parasitic bradyzoites, which permitted these infections to be diagnosed microscopically as sarcocystosis.

Influence of infection intensity on predilection sites in swine trichinellosis

The muscular distribution of Trichinella spiralis or T. britovi was studied by digestion in 59 experimentally infected pigs and seven wild boars. Crus muscle was the predilection site in 89.3% of 28 heavily infected swine with 146-3634 larvae per gram (lpg), but in 51.6% of middle to light infections (0.005-59 lpg) the basis of the tongue showed higher larval densities than the crus muscle. The basis of the tongue was also the predilection site in 71.4% of wild boars. Highest counts in other muscles were found only in lightly infected pigs. The influence of intensity of infection, host species, and Trichinella species on muscle distribution is discussed.

Infection with Toxoplasma gondii RH and Prugniaud strains in mice, rats and nude rats: kinetics of infection in blood and tissues related to pathology in acute and chronic infection

Since mice and rats are the most studied models of experimental toxoplasmosis, the aim of this work was to analyze the outcome of Toxoplasma infection in mice, rats and congenitally athymic nude rats; for this purpose, the parasitic load in different organs and the anatomic-pathological characteristics of infection were investigated in these animals. The data obtained after infection with two different strains and stages of Toxoplasma gondii (RH tachyzoites and Prugniaud cysts) concerned the following organs: brain, mesenteric lymph nodes, blood, spleen, heart, lungs, diaphragm and liver. In Fischer rats, the infection with either the Prugniaud or the RH strains displayed similar characteristics: after a peak in the parasite load, a complete disappearance of parasites was observed, except in the brain of Prugniaud strain-infected rats where toxoplasmas were evidenced throughout the experiment. In OF1 mice, where infection by the RH tachyzoites was lethal, infection with the Prugniaud strain led to survival; the parasitic burden peaked in the different organs and was then undetectable, except in the brain where toxoplasmas were still present during the chronic phase. Like mice, nude rats did not survive to the RH infection. Interestingly, for all the animals the observed histopathological changes in the infected organs, although more or less obvious in the acute phase, were not very severe in almost all cases. For instance, mice, although more susceptible to infection than rats, did not present more severe lesions. They consisted in a discrete inflammation with some focal areas of necrosis in some organs such as brain, liver and heart. Our results support the assumption that rats and nude rats constitute interesting experimental models relevant to either human acute toxoplasmosis, chronic toxoplasmosis, or disseminated toxoplasmosis in AIDS patients.

Vitamin B6-deficient diet plus 4-deoxypyridoxine (4-DPD) reduces the inflammatory response induced by T. spiralis in diaphragm, masseter and heart muscle tissue of mice

Animals fed diets deficient in vitamin B6 develop microcytic anemia, alterations of growth, and other pathologies. 4-deoxypirydoxine is a potent antagonist of vitamin B6 coenzyme which depresses IL-1, TNF and IL-6 and has anti-inflammatory properties. The aim of this study was to show the anti-inflammatory effects of 4-DPD on chronic inflammation caused by the nematode parasite T. spiralis, specifically on the recruitment and the activation of inflammatory cells. Two groups of mice, 6 weeks of age, were used: one was maintained on a vitamin B6-deficient synthetic pellet diet for 15 days before injection of the nematode, and administered an intraperitoneal injection (i.p.) of 4-DPD (250 microg/mouse) for 15 days (the first, 5 days before infection), and the second group was maintained on a normal diet for the total duration of the experiment. These two groups were then injected with 150 larvae (L1-T7 spiralis) per os. Chronic inflammation was caused by infection of treated or untreated mice with T7 spiralis parasite. After 14 days post-infection all mice developed a chronic inflammatory response. Mice fed with a B6-deficient diet showed a significant decrease in the number of cysts found in the diaphragm when compared to mice treated with normal diet. In addition, in all mice treated with vitamin B6-deficient diet plus 4-DPD the average body weight was significantly lower, compared to the mice on normal diet in all weeks examined. Moreover, in sections of the diaphragm, masseter and myocardium muscles, the infiltration of inflammatory cells, such as macrophages, lymphocytes, and eosinophils were more intense in untreated mice compared to those fed a vitamin B6-deficient diet. These results show that BALB/c mice infected with T. spiralis and fed a vitamin B6-deficient diet plus the vitamin B6 antagonist, 4-DPD, prolong the time of invasion of the larvae in the muscle cells, influence the recruitment of inflammatory cells and the intensity of the inflammatory reaction compared to infected untreated mice (control).

Prevalence of Sarcocystis spp. in meat-producing animals in Iraq

The prevalence of Sarcocystis spp. infection was investigated in 605 sheep, 826 goats, 1080 cattle, 580 water buffaloes and 36 camels slaughtered from 1992 to 1996 in the Baghdad area (Iraq) using naked eye examination for macroscopic sarcocysts, and peptic digestion, muscle squash, squeezing methods and indirect fluorescent antibody test (IFAT) for microscopic types. The intestinal stages of the parasite were also studied in dogs experimentally fed with tissues containing microscopic cysts. The percentage prevalence of macroscopic cysts were 4.1, 33.6, 0.2, 15.6 and 0, and of the microscopic type, 97.0, 97.4, 97.8, 82.9 and 91.6 for the above-mentioned hosts, respectively. Among the different organs examined, macroscopic cysts were found to be highest in the oesophagus and the lowest in the heart. Peptic digestion method gave the highest rate (93.3%) followed by indirect fluorescent antibody test (IFAT) (88.6%), squeezing (81.3%), and muscle squash (81.2%). Each infected dog shed a total of about 150-200 million sporocysts. Histologically, developmental stages of the parasite were detected in the small intestinal mucosa of the dogs on Days 7 and 13 post-infection.

Prevalence and risk association for Trichinella infection in domestic pigs in the northeastern United States

To determine Trichinella infection in a selected group of farm raised pigs, 4078 pigs from 156 farms in New England and New Jersey, employing various management styles, were selected based on feed type (grain, regulated waste, non-regulated waste). The number of pigs bled from each farm were based on detecting infection assuming a 0.05 prevalence rate. Serum was tested by enzyme-linked immunoassay for antibodies to Trichinella spiralis. Seropositive pigs were tested by digestion at slaughter (when possible) for the presence of Trichinella larvae. Questionnaires completed at the time of serum collection were used to develop descriptive statistics on farms tested and to determine measures of association for risk factors for the presence of Trichinella-seropositive pigs. A total of 15 seropositive pigs on 10 farms were identified, representing a prevalence rate of 0.37% and a herd prevalence rate of 6.4%. A total of nine seropositive pigs and one suspect pig from six farms were tested by digestion; four pigs (representing three farms) harbored Trichinella larvae at densities of 0.003-0.021 larvae per gram (LPG) of tissue; no larvae were found in six pigs. Risk factors which were significantly associated with seropositivity included access of pigs to live wildlife and wildlife carcasses on the farm; waste feeding had no statistically significant association with seropositivity for Trichinella infection in pigs. The presence of Trichinella infection in pigs in New England and New Jersey has declined during the past 12 years when compared with previous prevalence studies.

Detection of Trichinella infection in slaughter horses by ELISA and western blot analysis

In order to determine the presence of Trichinella infections in horses slaughtered at an abattoir in Mexico, 147 serum samples were examined by two immunoenzymatic methods. Specific antibodies were detected by ELISA in 7% of the serum samples at a dilution 1:400 and in 10% at lower dilutions (1:20, 1:40) using Trichinella spiralis muscle larvae (ML) excretory/secretory (E/S) products. Serum samples from four naturally infected horses (confirmed by direct methods) gave negative O.D. values in an ELISA at a 1:400 dilution and only two of them were positive at a 1:20 and 1:40 dilutions. Serum samples from experimentally infected horses reacted by Western blotting with ML components with molecular weights of 47, 52, 59, 67, 72 and 105 kDa which correspond to the TSL-1 antigens. Serum samples from the four naturally infected horses and from the abattoir horses that were positive in ELISA using E/S antigens recognized several ML components, some of them reacted with all the TSL-1 antigens mentioned above and others recognized preferentially two or three of these molecules. Since the serologic assays may not offer the sensitivity required in the diagnosis of horses trichinellosis and the direct methods had not always been useful in the detection of larvae in horsemeat related to trichinellosis outbreaks in Europe, it is proposed that additional assays are performed to determine Trichinella infection in horses. These can include detection of parasite antigens by ELISA and Dot ELISA or PCR, which in turn may also help to determine the presence of the parasite in early and late infections of horses.

Extracerebral infections of Acanthamoeba spp. in mice. pathomorphological changes in tissues of infected animals

A variety of Acanthamoeba spp. pathogenic strains were isolated from water pools in the area of Poznań. In many cases amoebae invaded lungs, kidney heart, liver and diaphragm causing significant changes in these Organs. The presence of amoeba outside of CNS was found mainly in the early periods of infection. Amoeba isolated from different organs of dead animals did not exhibit any specificity in relation to the organs in following infections. Infection with both low-and high-virulent strains resulted in pathomorphological changes of similar character. However, changes induced by low-virulent parasites developed later and were less extensive.

Tissue migration of Elaphostrongylus spp. in guinea pigs (Cavia porcellus)

Third-stage larvae of Elaphostrongylus cervi, originating from red deer (Cervus elaphus), first reached the central nervous system (CNS) of guinea pigs (Cavia porcellus) 11 days postinfection (DPI). Neurologic signs were seen between 11 and 62 DPI in 4 of a total of 18 infected guinea pigs killed up to 112 DPI. Animals showing signs had 3 or more larvae in the CNS. Only 1, of a total of 1,114 larvae recovered, had developed to the fourth stage at 40 DPI. A direct tissue migration by third-stage larvae to the CNS was revealed by pressing and digesting almost all body tissues and by histological examination. Larvae penetrated through the stomach wall into the peritoneal cavity and then through the diaphragm into the pleural cavity. Many became encapsulated by inflammatory cells in the omentum, abdominal mesentery, mediastinum, and just beneath the liver capsule and lung pleura. A total of 44 larvae succeeded in reaching the CNS, apparently by migrating from the body cavities into muscles of the lateral body wall and entering the vertebral canal, likely along spinal nerves. Data were not consistent with a hematogenous migratory route that has been proposed previously. Few third-stage larvae of E. alces, originating from moose (Alces alces), were able to penetrate the gut of guinea pigs and none reached the CNS.

Prevalence of Toxoplasma gondii in Canadian market-age pigs

During 1991 and 1992, 2,800 market-age pigs were sampled at federally inspected abattoirs from across Canada. Anti-Toxoplasma gondii IgG at titers of > or =1:32 were found in 240 pigs examined by a commercial, latex agglutination test. Seroprevalences ranged from 3.5 to 13.2% in the different regions of the country. Tissue hybridization studies using a previously developed probe demonstrated T. gondii ribosomal RNA in 9 of 36 animals, whereas mouse bioassay testing of heart muscle and diaphragm from all 2,800 pigs failed to demonstrate the presence of infective stages of T. gondii in tissues. Although serology results from this study indicated that Canadian market-age pigs are infected with T. gondii at rates similar to those reported from other parts of North America, mouse bioassay results suggested that Canadian pork products contain low levels of infective organisms. This apparent discrepancy suggests that serological evidence of T. gondii infection in pigs alone does not accurately assess the public health risks associated with consuming improperly cooked pork products.

Sensitivity of artificial digestion and enzyme immunoassay methods of inspection for trichinae in pigs

Forty-seven pigs were infected with varying doses of Trichinella spiralis and tested for evidence of infection by serology, using an enzyme immunoassay (EIA), and by artificial digestion methods. Using a 1-g sample, as prescribed in accordance with European Union (EU) directives, the sensitivity of the pooled-sample artificial digestion method was between three and five larvae per gram (LPG) of tissue. Using a 5-g sample size, in accordance with methods described in the U.S. Code for Federal Regulations, and as required for the inspection of horses exported to the EU, the sensitivity of the test was increased to approximately 1 LPG. Serological testing by EIA detected pigs with as few as 0.02 LPG, but detection times varied from 4 to 8 weeks after infection. Mean postinoculation times for detection by serology were 32 to 42 days. On the basis of these results, it is clear that digestion testing using a 5-g sample size is the only method of those tested here that is completely reliable for detection of trichinae infection at a level that will protect public health. Both digestion testing using a 1-g sample and EIA have drawbacks. However, EIA remains a highly effective tool for epidemiological purposes and for monitoring trichinae infection on the farm.

Sarcocystis suihominis detected for the first time from pigs in Japan

Sarcoystis suihominis was detected for the first time in Japan from the heart and diaphragm of 5 out 600 older culled breeding pigs slaughtered in Saitama Prefecture, Japan. Fresh cysts were 1,080-2,040 x 106-170 microns in size. Bradysoites measured 15 x 4 microns on average. The cyst wall was usually observed thick, 4-6 microns, and striated, but occasionally thin and smooth according to the difference in sectioning angle and in portion of cysts. Scanning electron microscopy showed that many palisade-like villar protrusions, 6-6 x 0.3-0.5 microns in size, were closely folded onto the surface of cyst. A small number of microtubules were seen in the core of protrusion. No dogs nor domestic cats fed with 20 fresh cysts each excreted oocysts or sporocysts in the feces throughout the experimental period of 30 days.

Diagnosis of porcine trichinellosis: parasitological and immunoserological tests in pigs from endemic areas of Argentina

In order to compare the reliability of serological and parasitological techniques for the diagnosis of porcine trichinellosis from endemic areas in Argentina, 116 pigs were studied: 61 animals from two separate outbreaks and 55 from a small abattoir. Direct diagnostic techniques included trichinoscopy and the artificial digestion method. Indirect diagnostic tests used in this study were the enzyme-linked immunosorbent assay (ELISA), employing the excretory-secretory products of muscle larvae (ML) as antigen, and the indirect immunofluorescence assay using as antigen ML in suspension (IIF-susp), cryostat sections of infected rat muscle or of free ML (IIF-slide). The percentage of parasitologically positive pigs was invariably lower than that of serologically positive animals (IIF-slide), even when digestion studies were carried out individually with a greater amount of muscle sample than required by current regulations. Close correlation was found between IIF using as antigen tissue sections and IIF using free ML sections, while IIF-susp proved unsuitable for diagnosis since this assay presented a high percentage of false negative results (20%). The IIF-slide technique proved positive in all parasitologically positive animals. ELISA rendered a lower percentage of positive reactions than IIF-slide, especially when worm burden was low. Since most parasitologically positive animals rendered at least two positive serological tests (two variations of IIF or IIF plus ELISA), those negative by digestion and positive by two serological methods were strongly suspected of having trichinellosis. Upon studying swine from a abattoir it was found that 9% of the pigs were positive when assayed by two serological techniques, but Trichinella spiralis infection could not be parasitologically confirmed. To sum up, serological methods may be used for screening all pigs and positive findings should be tested by the digestion method by analysing a greater quantity of pork than that required by current regulations, above all in areas with reported clinical trichinellosis in humans, to ensure that the pork is safe for human consumption.

Distribution of Trichinella spiralis larvae in muscles from a naturally infected horse

Epidemiological investigations conducted during 10 trichinellosis outbreaks between 1975 and 1994 showed that horse-meat was the probable source of infection. Though hundreds of thousands of horses have been examined at abattoirs in America and Europe to detect Trichinella infection by artificial digestion or trichinelloscopy, an infected horse has never been detected during routine analysis, which consists of examining 1 g of tissue muscle from the diaphragm. In November 1996, a naturally infected horse imported from Romania was detected in Southern Italy. The parasite was identified as Trichinella spiralis by random amplified polymorphic DNA analysis. Artificial digestion of tissue samples from 60 different muscles from 13 different sites of the infected horse carcass showed that M. levator Labii maxillaris, M. hyoideus transversus, and M. buccinator were the 3 most infected muscles. Muscles from the tongue, the masseter, and the diaphragm, which have normally been considered the muscles of choice for diagnosis, were the 4th, 6th and 13th most infected muscles, respectively. When comparing body sites, muscle tissues from the head showed the highest level of infection, followed by muscles from the neck. This finding may explain the negative results that have been obtained in the past during routine examination of the diaphragm of horses.

Diagnosis of trichinellosis in swine by enzyme immunoassay, using a synthetic glycan antigen

OBJECTIVE

To assess performance of a synthetic carbohydrate antigen for use in an enzyme immunoassay for diagnosis of trichinellosis in swine. ANIMALS AND SAMPLE POPULATION: 47 York X Duroc pigs and field sera from 265 farm pigs raised under various management systems.

PROCEDURES

Each of 47 pigs was inoculated with 25 to 500 Trichinella spiralis larvae, and blood samples were obtained weekly. At postinoculation week 12, pigs were euthanatized, and tissues recovered from the tongue and diaphragm were digested to determine worm burden. Serum samples from experimentally infected pigs and sera obtained from pigs on a farm were tested by enzyme immunoassay, using standard excretory-secretory and synthetic glycan antigens.

RESULTS

Of the 47 pigs, 46 (97.8%), with worm burden ranging from 0.02 to 248.8 larvae/g of tissue in the tongue and diaphragm, tested seropositive using both antigens. Time of seroconversion varied among pigs and was negatively correlated with intensity of infection. Minor differences were observed in time of seroconversion between the 2 antigens in 11 of 46 pigs, suggesting some differences in the antibody response. One pig with a worm burden of 0.01 larva/g was not detected by enzyme immunoassay using either antigen. Background values obtained using the 2 antigens did not differ among confinement-raised pigs, but background values for pigs raised outdoors on dirt lots were significantly lower using the glycan antigen Low-level, naturally acquired T spiralis infections in pigs were detected in most instances by use of both antigens, although there were some differences in antibody responses of infected pigs.

CONCLUSION

The synthetic glycan antigen has potential for replacing excretory-secretory antigens as a standardized reagent for diagnosis of trichinellosis in pigs.

Ultrastructure of the cyst wall of Sarcocystis sp. in roe deer

Samples of heart, tongue, oesophagus and diaphragm muscle from twenty-two naturally infected roe deer (Capreolus capreolus) harvested in central Italy were examined for sarcosporidiasis. The structure of Sarcocystis spp. muscle cysts was examined by light and electron microscopy. Only one type of thin-walled cyst was distinguished by light microscopy. Electron microscopy showed cysts having a thin highly folded primary cyst wall, without fibrillar material, that formed thin hair-like protrusions often having a T-form, especially close to host cell mithocondria. The cysts appeared to belong to a single Sarcocystis sp. so that all the animals had monospecific infections. This cyst was compared with cysts described in other cervid in an attempt to determine if single or multiple species of the genus Sarcocystis occur in the Cervidae. Apparently, a single Sarcocystis sp. with a low specificity for the intermediate host can infect the Cervidae.

Status of Trichinella spiralis in domestic swine and wild boar in Canada

Evidence of the status of trichinellosis in Canada's national swine herd is provided from data acquired through national surveillance programs and from a prevalence study of Trichinella in wild boar and domestic swine. More than 500,000 swine tested at abattoirs in ongoing animal health surveys since 1980 and 2 national swine serological surveys (1985 and 1990) showed no evidence of Trichinella infection, except for 3 occurrences in a small infected zone in Nova Scotia. The prevalence study of domestic swine and wild boar was conducted for the prevalence of Trichinella after an epidemiological investigation of a 1993 outbreak of human trichinellosis in Ontario showed that the disease was linked to the consumption of wild boar meat originating from 2 farms in the province. Sera and tissues were collected from 391 wild boar and 216 domestic swine originating from 228 farms in Quebec, Ontario, Manitoba and Saskatchewan. The survey examined approximately 37% of the wild boar slaughtered in Canada in 1994. A pepsin-HCl digestion test of the tissues and an ELISA performed on the sera did not yield any positive results. These findings and the lack of human cases of Trichinella from the consumption of Canadian pork for nearly 2 decades suggest that the parasite has been rare in domestic swine and wild boar raised in Canada. Trichinella spiralis has only been found sporadically in swine in a small region within Nova Scotia.

[Frequency of human trichinosis in Concepción and Arauco, Chile: study in autopsied persons at the Concepción Medico-Legal Service. June 1996-March 1997]

The frequency of trichinosis was determined in 300 dead persons, residents in the provinces of Concepción and Arauco, and requiring necropsy at the Servicio Medico Legal of Concepción. Diaphragm muscle samples were taken from June 1996 to March 1997. The diagnosis was made by trichinoscopy and artificial digestion techniques. Five samples (1.67%) were positive. There was not differences between sexes. Positive cases were found mainly among 30 to 49 years old people belonging to middle-lower class. Both diagnostic techniques showed different sensitivity as a consequence of the parasitic load and on the contrary, the artificial digestion was less sensitive when the cyts were fully calcified.