Experimental infection with Toxoplasma gondii in broiler chickens (Gallus domesticus): seroconversion, tissue cyst distribution, and prophylaxis.

Toxoplasma gondii is a widespread zoonotic protozoan that infects most species of mammals and birds, including poultry. This study aimed to investigate the course of T. gondii infection and the efficacy of diclazuril and Artemisia annua in preventing infection in experimentally infected chickens. Seventy-five 1-month-old chickens, female and male, were randomly divided into five groups (n = 15 each) as follows: (1) uninfected untreated (negative control, NC); (2) infected with T. gondii genotype II/III isolated from a wild cat (group WC); (3) infected with T. gondii genotype II isolated from a domestic cat (group DC); (4) infected with T. gondii domestic cat strain and treated with the anticoccidial diclazuril (group DC-D); and (5) infected with T. gondii domestic cat strain and treated with the medicinal plant Artemisia annua (group DC-A). Clinical signs, body temperature, mortality rate, weight gain, feed conversion ratio, hematological parameters, and the presence of T. gondii-specific IgY antibodies were recorded in all groups. Five chickens per group were euthanized 28 days post-infection (p.i.) and their brains, hearts, and breast muscle tested for T. gondii by mouse bioassay and polymerase chain reaction (PCR). No clinical signs related to the experimental infection were observed throughout the study period. T. gondii-specific antibodies were detected by day 28 p.i., but not in all infected chickens. Overall, T. gondii DNA was detected (bioassay or tissue digests) in all infected and untreated chickens (10/10), while viable parasite (bioassay) was isolated from 7 out of 10 chickens. The parasite was most frequently identified in the brain (7/10). There were no differences in the T. gondii strains regarding clinical infection and the rate of T. gondii detection in tissues. However, higher antibody titers were obtained in chickens infected with T. gondii WC strain (1:192) comparing with T. gondii DC strain (1:48). A. annua reduced replication of the parasite in 3 out of 5 chickens, while diclazuril did not. In conclusion, broiler chickens were resistant to clinical toxoplasmosis, irrespective of the strain (domestic or wild cat strain). The herb A. annua presented prophylactic efficacy by reduced parasite replication. However, further studies are required aiming at the efficacy of diclazuril and A. annua for the prevention of T. gondii infection in chickens using quantitative analysis methods.

Cysticercosis of the Pectoralis Major: A Case Report and Review of Literature.

Cysticercosis is a condition caused by the encysted larval form of Taenia solium (pork tapeworm). The commonest system affected is the central nervous system. Symptomatic primary muscle involvement is a rare phenomenon. We present a case of a 19-year-old male who presented with a solitary cystic swelling in the right infraclavicular area. Magnetic resonance imaging revealed a cystic mass in the right pectoralis major muscle. The cyst was excised and submitted for histopathology. The diagnosis of cysticercosis was confirmed on histopathology of the excised cyst.

Isolation of Toxoplasma gondii from the keel-billed toucan (Ramphastos sulfuratus) from Costa Rica.

Pectoral muscles from a captive keel-billed toucan (Ramphastos sulfuratus) from Costa Rica were fed to a Toxoplasma gondii-free cat, and the cat shed oocysts. Laboratory mice fed these oocysts developed antibodies to T. gondii in their sera and T. gondii tissue cysts in their brains. The DNA extracted from the brains of infected mice was characterized using 10 polymerase chain reaction-restricted fragment length polymorphic markers (SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico). The isolate designated TgRsCrl was found to be non-clonal with Type I, II, and III alleles at different loci. This is the first isolation of T. gondii from this host.

Prevalence of encysted apicomplexans in muscles of raptors.

An acid-pepsin digestion technique was used to examine portions of breast muscle and heart from raptors for encysted protozoans. Apicomplexan zoites were present in 52 (45.6%) of the 114 samples examined: 11 of 12 (91.7%) red-shouldered hawks (Buteo lineatus), 20 of 34 (58.8%) red-tailed hawks (Buteo jamaicensis), two of seven (28.6%) Cooper's hawks (Accipiter cooperi), three of four (75%) sharp-shinned hawks (Accipiter striatus), one (100%) Mississippi kites (Ictinia misisippiensis), one of two (50%) American kestrels (Falco sparverius), one bald eagle (Haliaeetus leucocephalus), one of two (50%) golden eagles (Aquila chrysaetos), one of three (33%) turkey vultures (Cathartes aura), two of three (66.7%) black vultures (Coragyps atratus), three of six (50%) great-horned owls (Bubo virginianus), five of 15 (33.3%) barred owls (Strix varia), and one of 12 (8.3%) screech owls (Asio otus). Encysted protozoans were not observed in digests of tissues from three broad-winged hawks (Buteo platypterus), four ospreys (Pandion haliaetus), and five barn owls (Tyto alba). Apicomplexan cysts resembling Sarcocystis species were observed in tissue sections of muscles from 28 (37.8%) of 74 raptors.

Incidence of sarcocysts in skeletal muscles of horses.

The incidence of sarcocysts was examined in postural, propulsive and respiratory muscles from 74 horses ranging in age from mid-gestation to 14 years post-natal. Cryostat sections were stained for myosin adenosine triphosphatase (ATPase) at pH 9.5 and the type of muscle fibre containing sarcocysts was identified. Sarcocysts were found in muscles from three animals, all aged 1 year or more. Counts showed that they displayed no preference for any particular muscle. However, fibres with a high activity for myosin ATPase were preferentially colonized. Transverse sectional profiles of sarcocysts showed a wide variation in size, shape and wall thickness. Both the proportion of horses infected and the intensity of infection per animal were considerably lower than those reported in other studies.

Bear meat trichinosis with a concomitant serologic response to Toxoplasma gondii.

A severe case of trichinosis occurred following the ingestion of raw meat from a common black bear, Ursus americanus, that was shot in Butte County, California. Examination of steaks cut from the bear revealed heavy infection with T. spiralis. A good clinical response was obtained following treatment with prednisone (1 mg/kg body weight per day) and thiabendazole (50 mg/kg body weight per day); no toxic effects were observed. In comparison with the pre-treatment biopsy, a more intense inflammatory response was seen following the administration of thiabendazole. Nevertheless, a muscle biopsy taken several months after discharge still showed well-encapsulated, morphologically intact larvae. In addition to the expected immunological responses to T spiralis, a marked rise in titer of antibodies to Toxoplasms gondii was observed by the fluorescent antibody and Sabin-Feldman dye test methods. Since toxoplasma infection of muscle is widespread in man, it is possible that an unrelated disease of muscle could result in stimulation of anti-toxoplasma antibodies similar to the findings in polymyositis and dermatomyositis. Alternatively, the possibility that a dual infection was acquired from the bear meat cannot be excluded.