Disseminated ascariasis: a case report

A very unusual case of ascariasis is reported. There was massive migration of worms from the small bowel to the liver, and probably thence to the heart and lungs, where adult worms were demonstrated. The cause of death was pulmonary embolism, adult worms blocking the main pulmonary arteries with superimposed thrombosis. This is believed to be unique.

Cysticercosis in cattle in Senegal

The hearts of 51, and the masticatory muscles of another 51 cattle from the slaughter-house in Dakar, were examined by careful dissection. Cysticerci and/or cystic lesions were found in 13.7% of the hearts and in 25.5% of the masticatory muscles. The cystic lesions were examined histologically in an attempt to identify Taenia saginata cysticerci. A final infection rate of 5.8% in hearts and 15.7% in masticatory muscles was thus obtained. Lower percentages were recorded after inspecting 2088 slaughtered cattle by the routine meat inspection technique.

Early course of infection in susceptible and resistant strains of mice, using [3H]uridine-labeled Trypanosoma brucei subsp. brucei

A radioisotopic technique utilizing [3H]uridine was developed to determine the tissue distribution of intravenously inoculated Trypanosoma brucei spp. brucei in susceptible (Swiss-Webster) and resistant (deer) strains of mice. The reliability of the technique was tested by using unincorporated [3H]uridine and heat-killed (labeled) trypanosomes in parallel experiments. The inoculations with viable (labeled) organisms showed that during the initial 24 h T. brucei subsp. brucei was cleared from the bloodstream of deer mice to a significantly greater extent than in Swiss-Webster mice. In addition, significantly more radioactivity was found in the liver, spleen, and kidneys of the deer mice. Autoradiographs of trypanosomes in selected tissues supported the distribution observed with labeled organisms. All of the above experiments involved the highly virulent, monomorphic bloodstream form of T. brucei subsp. brucei. Similar experiments with less virulent tissue culture-adapted trypanosomes showed that these organisms were readily cleared from the bloodstream, even in highly susceptible Swiss-Webster mice. The results suggest that avoidance of phagocytosis may be an important virulence factor of T. brucei subsp. brucei and contributes to the variation observed in species and strain susceptible to trypanosomiasis.

[Studies on the therapeutics of experimental toxoplasmosis. II. Effect of acetylspiramycin alone or in combination with an immunopotentiator (CSP-II) or sulfamethopyrazine on Toxoplasma multiplication in the heart of mice acutely and chronically infected with Toxoplasma gondii (author's transl)]

Normal mice acutely and chronically infected with the S-273 strain of T. gondii, were treated with acetylspiramycin (ASPM) alone, 8 mg/mouse/day, per os, or in combination with an immunopotentiator (CSP-II), 10 mg/mouse/day, intraperitoneally, or sulfamethopyrazine (SMPZ), 2 mg/mouse/day, per os, for a period of 4 weeks. In the acute cases, a 99.4% cyst reduction was obtained with ASPM alone and no cysts were seen in the brains of mice treated with ASPM in combination with CSP-II or SMPZ. The organisms were significantly eradicated in the brain and heart tissues of mice treated with ASPM alone or in combination with CSP-II or SMPZ as shown by subinoculation to normal mice and the negative latex hemagglutination titers of the recipient mice. In the chronic cases, a cyst reduction of 52.4% was obtained with mice treated with ASPM in combination with CSP-II. A cyst reduction of 34.6%, 32.9% and 20.8% was obtained in the ASPM alone, CSP-II alone and ASPM in combination with SMPZ treated groups, respectively. A comparative clearing of the organisms in the heart tissues of mice treated with ASPM in combination with CSP-II was obtained compared to the other treatment groups but not in the brains of all groups.

Helminths of the spotted seal, Phoca largha, from the Bering Sea

Fifty-five spotted seals, Phoca largha, from the seasonal pack ice of the Bering Sea were examined for helminth parasites. Twelve species of helminths were found: Anophryocephalus ochotensis, Diplogonoporus tetrapterus, Diphyllobothrium cordatum, Phocanema decipiens, Contracaecum osculatum, Dipetalonema spirocauda, Phocitrema fusiforme, Corynosoma semerme, C. strumosum, C. validum, C. villosum, and Bolbosoma sp. Six species are new host records (A. ochotensis, D. tetrapterus, D. cordatum, D. spirocauda, C. validum, and C. villosum).

Electron microscopic studies on microfilariae of Dipetalonema viteae and Litomosoides carinii: the occurrence of intracellular parasites after treatment with metrifonate or diethylcarbamazine

Microfilariae of Dipetalonema viteae and Litomosoides carinii were studied by means of electron microscopy after oral treatment of their hosts with metrifonate (3 x 100 mg/kg) or diethylcarbamazine (3 x 250 mg/kg). These dosages led to the disappearance of microfilariae from the peripheral venous blood. However, in numerous organs blood capillaries or interstitial spaces contained degenerating microfilariae. In these cases the cytoplasm of the microfilarian cells was completely lysed, whereas the cuticle seemed to be unaffected, at least initially. Microfilariae of both species were also often found intracellularly especially in liver and muscle cells after application of both drugs. The intracellular microfilariae, however, had fewer or even no lesions, suggesting that they might escape the activity of the drug.

Dirofilaria immitis infection in man: report of a case of the infection in heart and inferior vena cava from Japan

Two slender nematodes were incidentally found at autopsy in the heart and inferior vena cava of a 36-year-old Japanese man who died of liver cirrhosis. The parasite from the heart measured 29.5 cm by 0.87 mm, and that from the inferior vena cava 26.5 cm by 0.85 mm. The worms were identified as non-gravid adult female Dirofilaria immitis. This is the fourth case of infection with D. immitis in the heart and large vessels.

[Studies on the therapeutics of experimental toxoplasmosis. I. Effect of acetylspiramycin and spiramycin on the intracardiac Toxoplasma multiplication in mice infected with Toxoplasma gondii (author's transl)]

A total of 329 human serum samples were collected from the clinics of internal medicine of Obihiro city and its suburbs and were screened for Toxoplasma antibody level using the latex agglutination microtiter method (LA). Ninety-one (27.7%) were positive, 4 (1.2%) were equivocal and 234 (71.1%) were negative. Positive reactants were highest in the age group of 55-74 years old. A relatively high percentage on positive reactants was observed in patients with accompanying cardiac and cerebral disorders, i.e., 33.3% and 35.6%, respectively. ICR-JCL mice were infected with 10(2) tachyzoites of the S-273 strain of T. gondii intraperitoneally. Chronic cases were obtained from those mice which survived the first infection without any further challenge 1 month later. Therapy was carried out by administering acetylspiramycin or spiramycin per os at a dose of 8 mg/0.5 ml per mouse per day for 30 days. After the end of therapy, brain and heart emulsions were made, and passaged to clean mice and observed for 30 days. Antibody titers were also monitored during the course of treatment using the LA microtiter method. In the acute cases, antibody titers were observed to gradually increase from the end of treatment up to 10 weeks. Antibody titers of the chronic cases were maintained at high levels before the start of treatment and up to its termination. Most of the mice subinoculated with brain emulsions obtained from the acute cases, both in the control and treatment groups, died. However, all of the mice subinoculated with heart emulsions from both treatment groups, survived. In the chronic cases, all mice subinoculated with brain emulsions from all groups died. A few survived the heart passages from both treatment groups, however, they showed very high reactions to the LA microtiter method.

Micronema in man: third fatal infection

Micronema, normally free-living in soil and humus, rarely invades and reproduces in the central nervous system, kidneys, lungs, maxillae and nasal cavity of equines. Two Micronema infections causing fatal meningoencephalomyelitis in man have been reported from Canada and Texas. Here we report a third infection in a 54-year-old black man, resident of Washington, D.C., who probably acquired the infection from decubitus ulcers. The worms in this patient were in the liver, heart and brain. The Micronema species was not identified.

Further studies on the development of Wuchereria bancrofti in laboratory animals

In an attempt to obtain a small animal laboratory model for Wuchereria bancrofti Mongolian gerbils and hamsters were infected with third-stage larvae of strains of the parasite from Indonesia and China. Gerbils were necropsied at 7 to 591 days and larvae recovered up to 219 days. The third molt occurred on or before 10 days and worms found after 14 days were in the fourth stage. More worms were recovered early in the infection (7 to 30 days) than in older infections. The worms were usually recovered from the testes, pelt and carcass and heart and lungs. An adult male worm was recovered on one occasion from the lung of a gerbil at 92 days. The parasite was also found to develop in hamsters with results similar to those in gerbils. Gerbils and hamsters were given antithymocyte sera before and after infection and more worms were recovered and the worms larger in size in some treated animals. Continued studies with geographic strains of W. bancrofti in various animals should be encouraged in order to find a small laboratory animal model for the parasite.

Caprine toxoplasmosis: abortion, clinical signs, and distribution of Toxoplasma in tissues of goats fed Toxoplasma gondii oocysts

Thirteen goats (9 does and 4 bucks) were each inoculated orally with 10,000 infective Toxoplasma gondii oocysts. Three does and one buck were used as noninoculated controls. In 2 to 4 days after inoculation (DAI), inoculated goats became dull, pyrectic (40 to 41 C), and anorectic. Three goats died (10, 10, and 14 DAI) and two goats were killed (7 and 32 DAI) because they were moribund; also, 3 does aborted, 2 had weak kids, and 2 had dead fetuses. Toxoplasma was isolated from the placenta of three goats, and the fetal tissues of four goats. The control goats remained asymptomatic. The distribution of T gondii in blood and other tissues was studied by inoculation of mice with caprine tissues. Parasitemia was detected in 7 of 7 goats--beginning 4 DAI in 1 goat, 5 DAI in 5 goats, and 8 DAI in 1 goat. The parasitemia lasted 3 to 10 days. Toxoplasma was isolated from the milk of 2 goats at 12 and 14 DAI. Toxoplasma was isolated from 15 or more tissues of 5 goats killed 7 to 35 DAI and from 10 tissues of 2 goats killed 69 and 95 DAI.

Experimental infection of chickens with Ancylostoma caninum: migration and distribution of larvae in tissues

Two hundred one-day-old male white leghorn chickens (Gallus domesticus) divided into 4 groups were inoculated with a single dose of 500, 1000, 2000 or 4000 filariform larvae of Ancylostoma caninum. Larval recoveries were made from different tissues at intervals from 4 hours to 72 hours after infection. Larval migration in the heart took place within 4 hours in all the groups except group A with 500 larvae and in thoracic muscle at 8 hours. Larvae also migrated into liver, lungs and neck muscle within 12 hours and into leg muscle at 18 hours. No larvae were recovered from the muscles after 72 hours of infection. Larvae did not migrate into kidney, spleen and central nervous system throughout the experimental period.

A model for cardiopathy induced by Trypanosoma brucei brucei in mice. A histologic and immunopathologic study

The successful induction of pancarditis in mice by the use of Trypanosoma brucei brucei is reported. The sequential analysis of whole-organ sections demonstrated the presence of trypanosomes in the cardiac structures from the fourth week after infection. Parasites predominated on the endocardial and epicardial side but were also present in the valves, the conducting system, and the lymphatic system draining the heart, the latter being particularly evident in late infection. At the time of parasite invasion, deposits of IgM and IgG and of complement (C3) appeared in the tissues. Also at this time parasitemia reached a plateau, and the circulating specific antitrypanosomal antibodies, the serum Ig and C3, as well as the Clq activity, reached pathologic levels. Cellular response followed parasite invasion and appeared to be similar to that described in human African trypanosomiasis. In late infection, the draining lymph nodes showed a marked histiocytic proliferation, and the vessels became convoluted and distended. The suggested pathogenic mechanisms involve immunologic and mechanical factors. It is possible that the immunologic process prepares for a simultaneous or subsequent parasite invasion of the tissues with an associated inflammatory response. The partial obstruction of the lymphatic cardiac draining system probably accounts at least in part for the peculiar distribution of the parasite-induced lesions. A therapeutic trial was unsuccessful, but the persistence of trypanosomes in the tissues when circulating parasites were no longer detectable may account for relapses.

Coyotes and canine heartworm in California

Adult Dirofilaria immitis were found in the hearts of 43 of 115 coyotes (Canis latrans) trapped within a 50 km radius of the El Dorado County seat. Of mature coyotes, 45% were positive, with worm numbers averaging 9.0 in females and 16.2 in males. D. immitis microfilariae occurred in the peripheral blood and in lung smears. Microfilariae of Dipetalonema reconditum were present in 14 of the coyotes examined (12%). Several coyotes showed enlarged hearts with gross pathological changes.

Dirofilaria immitis in red foxes in Illinois

Dirofilaria immitis was found in 8 of 225 (3.6%) red foxes (Vulpes vulpes) collected from fur buyers and trappers in Bond, Clinton, DeKalb, Edgar, Ford, Jasper, Moultrie, and Richland counties, Illinois. Infections ranged from 1 to 23 nematodes per fox. The finding of D. immitis in red foxes represents a new host record for the state.

Occurrence of (Dirofilaria immitis) in gray fox (Urocyon cinereoargenteus) in Alabama and Georgia

The occurrence of Dirofilaria immitis in gray fox (Urocyon cineroargenteus) was determined by gross examination, blood samples, and filtered tissue sediments in a sampling of 149 gray foxes taken from Alabama and Georgia during the 1977-78 trapping season. Microfilariae were not found in blood samples obtained from 24 of these gray foxes. Three of 82 male foxes (3.7%) and 1 of 67 female foxes (1.5%) were infected with heartworm. D. immitis rate of infection was 1 of 19 (5.3%) and 3 of 130 (2.3%), respectively, in juvenile and adult gray foxes. Single sex infections with D. immitis occurred in 4 of the 6 foxes, with a maximum nematode burden of approximately eight. Two other infected foxes were encountered separate from this study.

Parasitemia and tissue infection in sheep fed Toxoplasma gondii oocysts

The distribution of Toxoplasma gondii in blood and other tissues of nine adult sheep experimentally infected with T. gondii oocysts was studied by inoculation of mice with ovine tissues. Parasitemia was detected in five sheep 6 to 11 days after inoculation (DAI) and lasting usually for 1 to 2 days. Toxoplasma gondii was isolated from numerous internal organs of five sheep killed between 7 and 28 DAI and from eight organs of a sheep killed 64 DAI. Of the three sheep killed 117, 118, and 119 DAI, T. gondii was isolated only from brain, heart, diaphragm, skeletal muscle, and intestine. Skeletal muscle was infected in all sheep. More mice became infected after inoculation with chronically infected tissues digested in 1% trypsin than undigested tissues. Results indicate that skeletal muscle and brain should be used for parasitological surveys in sheep.

Radiographic changes associated with developing dirofilariasis in experimentally infected dogs

Experimental heartworm infection was established in ten dogs. Five had mild infections (8 to 21 worms) and five had severe infections (41 to 96 worms). After larval inoculation, dogs were radiographed each month for 1 year to evaluate cardiopulmonary changes occurring as the heartworm disease developed. Changes seen radiographically during the first year of heartworm infection were related to the magnitude of the worm burden. In mild infections, changes mainly involved the terminal portion of the right caudal lobar pulmonary artery and were minimal. In severe infections, changes mainly involved the entirety of the right caudal lobar pulmonary artery. In some dogs, an increase in size of the right cranial lobar pulmonary artery was seen. Gross changes in the size of the right ventricle and main pulmonary artery did not frequently occur during the first year.