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Six littermate laboratory-raised coyotes (No. 1-6) were used to study the transmission of Toxoplasma gondii from cats and mice, and Toxocara canis and Isospora canis from dogs and mice. Coyotes 1 and 2 were inoculated orally with 1,000 infective oocysts of the TC-1 strain of T gondii; coyotes 3 and 4 were fed mice infected with tissue cysts of the TC-1 strain of T gondii. Eight days after inoculation with T gondii, the same 4 coyotes were exposed to Toxocara canis: coyotes 1 and 2 were inoculated orally with 500 embryonated eggs, and coyotes 3 and 4 were fed mice infected with Toxocara canis. Fifteen days after exposure to Toxocara canis, the same 4 coyotes were fed mice infected with I canis. Two coyotes (No. 5 and 6) did not receive any organism and they served as controls. All 4 inoculated coyotes remained clinically normal but became infected with all 3 organisms. Toxoplasma gondii was recovered from the brain, heart, diaphragm, and muscles of limbs of coyotes killed 49 and 66 days after inoculation with oocysts, but only from muscles of limbs of coyote 4, killed at 84 days, and from the brain and muscles of limbs of coyote 3, killed at 72 days after feeding infected mice. Control coyotes did not acquire any of the 3 infections.

Between 1975 and 1985, 49 in-patients suffering from Toxoplasmosis of head and neck lymph nodes, have been treated chirurgically at the ENT clinics of the universities of Cologne and Homburg/Saar. In the collective there are as much men as women. The patients have an average age of 30 years, the anamnesis is about 3 months. The patients were complaining of swellings of lymph nodes of the angle of mandible or of the submandibular region, but without fever or other signs of infection. Typically, the lymph nodes were not fixed but mobile, hard and indolent. Blood parameters and electrolytic levels are not pathologically changed. The patients do not feel sick in general. The diagnosis is to be confirmed by serological investigations, supported by lymph node histology (Lymphadenitis Piringer-Kuchinka). In the present study, three acute cases of Toxoplasmosis with high serological titers could be diagnosed. The differential diagnosis of the lymphadenitis toxoplasmotica will be discussed.

The importance of the role of toxoplasma oocysts in the mode of spread of the infection for men and animal has differently been estimated. In own earlier experiments, we found out that the transmission of the infection by means of oocysts from cat to cat is not the rule. In a similar experimental setup, we tested now whether rabbits can be infected by getting into contact with faeces of cats containing sporulated toxoplasma oocysts (see table 1). 8 toxoplasma-free rabbits and two toxoplasma-free cats as control were placed on infectious faeces of 10 cats (group 1-8). As further controls served four non-infected rabbits being kept in the same cage (group 11-12). Four of eight rabbits which had been placed on the infectious faeces and one control animal having had no intended contact with those faeces got infected. Our experiments show that the question whether domestic cats have any significance as source of infection with toxoplasms cannot generally be answered. It has to be differentiated each time which mammal gets into contact with oocysts.

Coccidia infections occurring in cats (Isospora, Cryptosporidium, Toxoplasma, Hammondia, Sarcocystis), peculiarities of their life cycles, and diagnostic, prophylactic and therapeutic possibilities are described; the problems of Toxoplasma infections of cats are intensively discussed. If the oocystshedding cat is suspected to be the source of infection for the owner, only both coproscopical and serological results allow an appropriate advice.

In October, 1977, an outbreak of toxoplasmosis occurred in patrons of a riding stable in Atlanta, Georgia; 37 became ill with toxoplasmosis or had serologic evidence by indirect fluorescent-antibody test of acute infection with Toxoplasma gondii (titer greater than or equal to 1:4096 or a positive fluorescent-antibody test for toxoplasma antibodies). Forty-nine additional patrons did not become ill. Two of the three adult cats from the stable were seropositive for toxoplasma, which was also recovered from the tissues of two kittens and four mice trapped near the stable. Patrons who spent most of their time at the end of the stable where a cat had defecated had the highest incidence of infection. Patrons who attended the stable daily had a higher attack rate than those who attended less frequently. No common meals were consumed, and dietary histroy eliminated meat as the source of infection. The data suggest that toxoplasma oocysts were the source of the infection.

Research has been carried out to determine the prevalence of toxoplasma infection in 1176 women of fertile age in Florence and province for 1984 so as to calculate expected congenital foetal risk of toxoplasmosis. Prevalence proved to be 22% in women aged from 15 to 20 and 60% in the 41-45 group, with an average annual sero-conversion rate of 1.5%. As pregnancy lasts 9 months, this rate is cut by 1/4, namely it drops from 1.5% to 1.125%. Transmission of the infection from mother to foetus occurs in about 1/3 of cases. 9256 pregnancies were reported in Florence and province. The expectation was therefore 104 primary infections and 35 infected newborns of whom 11-12 clinically diagnosable at birth. The estimated rate of toxoplasmosis in pregnancy is therefore 11% for Florence and foetal infection is about 4%. Two-thirds of the newborns with toxoplasma infection are asymptomatic but, if left untreated, they may develop serious neurological and behavioural sequelae. It is therefore necessary to learn the immune state with respect to toxoplasma for all fertile women before pregnancy and study negative findings during gestation.

Mice were immunized s.c. or intraintestinally with two injections of a temperature-sensitive mutant of Toxoplasma gondii (ts4). Nonpersistence of the vaccine strain was documented by subinoculation of tissues of a subgroup of mice 3 mo or more after the second immunization. Mice were immune to other-wise lethal parenteral challenges with tachyzoites of the M7741 strain or to peroral challenge with bradyzoites of the Me49 strain of T. gondii. Although two s.c. or intraintestinal immunizations did not completely protect against development of T. gondii in the brains of mice, fewer cysts developed in the s.c. immunized mice than in control mice (2 +/- 3 cysts/0.01 ml in immunized mice compared with 75 +/- 48 cysts/0.01 ml in controls (p less than 0.002)). Reduction in cyst number after intraintestinal immunization was more variable, but also statistically significant (p less than 0.02). Female mice were first immunized, then mated, and then challenged perorally. Neonates of the s.c. immunized mice were not protected. Neonates of intraintestinally immunized mice were protected in part (36% of 115) against congenital infection compared with controls (7% of 107).

The authors examined 1,027 persons divided into two groups by means of the toxoplasmin skin test. Group I contained 472 persons who owned domestic cats. Of these 255, i.e. 54.0% gave a positive reaction. Group II consisted of 555 persons who did not own cats. Of these 237, i.e. 42.7% reacted positively. A statistically significant difference at the 1% level of significance was assessed between the two groups. A difference of highest diagnostic importance was found in persons of unexposed occupations in the lowest age group, 14-19 years: 39.5% positive reactions among cat owners and 16.1% among those who did not own cats. The results support the assumption on the role played by domestic cats in the epidemiology of toxoplasmosis. An analysis of the ethology of the cat as regards its importance in the spread of Toxoplasma infection is the subject of the present study.

The occurrence of toxoplasmosis is described in the cat-mother and three kittens. Clinical symptoms were not significant: bristled hair, conjunctivitis, sneezing and hypertrophy of mandibular and popliteal lymph nodes. The titres of antibodies to Toxoplasma gondii were demonstrated in all kittens and also in the cat: Sabin-Feldman reaction titre 4-32, complement-fixing reaction titre 5-40. Microprecipitation in agar gel was positive in all animals. Oocytes of Toxoplasma gondii were eliminated through faeces by the cat and two 16-day-old kittens. An isolation trial on white mice with a negative finding of toxoplasmosis (inoculation of brain, liver and spleen samples) has demonstrated toxoplasmosis in all animals under study. Most probably the kittens were infected transplacentally.

Toxoplasma gondii infection of cats was studied in seven localities in Costa Rica. A total of 237 cats were tested for antibody by the dye test, and for oocysts by injection into mice. Toxoplasma was isolated from 55 (23%) and antibody was found in 109 (46%). Sixty percent of cats were infected as shown by shedding or antibody. Of the 55 isolations, 64% were from kittens without antibody and 36% from kittens with antibody. Almost half of the Toxoplasma isolations were made from the feces of kittens weighing less than 600 g, 35 cm in length, or under 2 months of age, of which 41% were shedding Toxoplasma. Six hundred and seventy-six homeowners in the seven towns were questioned about the number of owned and stray cats visiting their houses, the cats' pattern of roaming, food sources, types of food foraged, defecation sites outdoors and indoors, and location of fecal deposits in houses. Seventy-six percent of houses reported cats, which averaged 2.1 cats per house; about 80% were strays, and 99% lived outdoors part or all of the time. The cats visited from 5-12 (average 6) houses, foraging for food in garbage, hunting mice, rats, sparrows and insects. Of the 516 households reporting cats, 29% supplied some food in addition. In 14% of these houses cats defecated in the house, including the false attic and crawl space; they commonly defecated in front and backyards of houses, close to human habitation and accessible to intermediate hosts.

A total of 2643 persons in 5 different regions were examined for toxoplasmosis by the immunofluorescence test and toxoplasmin skin test. The presence in the house of cats and dogs was taken into account. In two of the five regions under study there was revealed an increased incidence of toxoplasmosis in persons keeping cats; this confirmed the role of these animals as a source of toxoplasmosis infection. The absence of such increase in the incidence of the disease in other regions in explained by the character of buildings admitting migration of cats or the presence in the given region of other active sources of infection. Toxoplasmosis incidence in persons who kept or didn't keep dogs displayed no significant difference.

Eight female, 12- to 34-month-old, specific-pathogen free cats were inoculated orally with Toxoplasma gondii cysts on day 0, then with Isospora felis and Isospora rivolta oocysts on day 39, and cysts of Hammondia hammondi on day 86 after inoculation with Toxoplasma. All cats shed oocysts of all 4 of these coccidia within 11 postinoculation days. The female cats were caged with 4 male Toxoplasma-free cats, starting 66 days after inoculation with Toxoplasma, until they were 5 to 6 weeks pregnant. Kittens that were born were housed with their mothers until necropsied or weaned. One 42-day-old kitten shed T gondii oocysts in feces. It was necropsied 2 days later and asexual stages of Toxoplasma (types D and E), gametocytes, and oocysts were demonstrated in sections of superficial epithelial cells of its small intestine. Lesions or forms of Toxoplasma were not demonstrated histologically in tis extraintestinal organs. Toxoplasma was not isolated from feces or tissues of the remaining 47 kittens born to these 8 queens. Toxoplasma was not isolated from the 4 male cats that were caged with infected females for 53, 59, 217, and 217 days. The source of toxoplasma infection in the kitten remained unknown but was considered unlikely to be congenital or through fecal contamination. Oocysts of I felis, I rivolta, and H hammondi were not found in the feces of any kittens, indicating that these coccidia are unlikely to be transmitted congenitally.

The authors compared a group of 197 women with different ascertained forms of toxoplasmosis and a group of 72 women with negative serological reactions on toxoplasmosis and hereby they revealed that the consumption of insufficiently heated meats as well as the contact with animals (rearing and digestion embowelling or drawing of coat) play an eminent part. As test animals above all cats were used. The results of the two groups were compared and a significant difference between them was ascertained for the consumption of the insufficiently heated meat as well as for the contact with the animals. The women with toxoplasmosis more frequently consumed insufficiently heated meat and had more contact with cats and other animals.

Toxoplasma gondii, the causal agent of toxoplasmosis, is a ubiquitous protozoan parasite which has the potential to infect man and all warm-blooded animals. It has as its definitive host the cat. Infections acquired by the human adult are generally subclinical. However, if acquired for the first time during pregnancy, the parasite can invade the developing foetus. Under these circumstances infection can result in abortion, stillbirth or production of live-born offspring with severe multiple organ involvement. Alternatively, offspring can be symptomless at birth but may manifest neurological and ocular sequelae of toxoplasmosis in later life. The degree of clinical involvement is thought to be dependent upon the time of acquisition of infection by the pregnant female. Recent investigations have been concerned with behavioural aspects of predator-prey relationships between cats and rodents. Since these aspects affect the spread of toxoplasmosis in the environment, they have strong epidemiological and ecological implications. Toxoplasma infection in the environment, they have strong epidemiological and ecological implications. Toxoplasma infection in mice is associated with subtle alterations in exploratory behaviour which are almost certainly maladaptive, rendering infected mice more susceptible to predation by cats. Consequently the behavioural abnormalities in mice associated with Toxoplasma infection would be of major importance for the continuation of the life-cycle of the parasite. Ingestion of Toxoplasma-infected mice leads to oocyst production in cats and this opens up the well-known pathway whereby Toxoplasma infection reaches the human species.

Recent advances in the epidemiology and life cycle of toxoplasmosis are reviewed. Cats play a key role. Toxoplasma has a coccidian-type entero-epithelial cycle with oocyst prodlction in the feline host. An extra-intestinal cycle occurs in both feline and non-feline hosts. The worldwide distribution and the public health significance of toxoplasmosis as a zoonosis is discussed, with particular reference to available data regarding Southern Africa.

The prevalence of Antibodies to Toxoplasma gondii in dogs and cats were determined by an indirect haemagglutination (IHA) test. 3% of the dogs' sera and 15.2% of that of the cats showed titres diagnostically significant of toxoplasmosis in humans; their possible role in transmission of toxoplasmosis to humans in Saudi Arabia is discussed.

After reviewing reports of the hosts, structure and life cycle of Toxoplasma, the genus is placed in the apicomplexan family Eimeriidae and the folllowing 7 species are recognized: Toxoplasma gondii (Nicolle & Manceaux) (type species) from about 200 species of mammals and birds, with oocysts in felids; Toxoplasma alencari (Da Costa & Pereira) from the frog Leptodactylus ocellatus; Toxoplasma brumpti Coutelen from the iguana Iguana tuberculata; Toxoplasma colubri Tibaldi from the snakes Coluber melanoleucus and Coluber viridiflavus; Toxoplasma hammondi (Frenkel & Dubey) (a new combination for Hammondia hammondi) from the house mouse with oocysts in the domestic cat; Toxoplasma ranae Levine & Nye from the leopard frog Rana Pipiens; and Toxoplasma serpai Scorza, Dagert & Iturriza Arocha from the toad Bufo marinus.

Toxoplasma gondii was isolated from muscles of 2 road-killed mule deer found near Bozeman, Mont, by feeding muscles to a Toxoplasma-free cat. The cat shed T gondii oocysts 5 days after ingesting muscles pooled from the 2 deer. One infective oocyst of this isolate of T gondii was lethal to mice.

We studied the prevalence of antibody to Toxoplasma gondii in 883 Costa Ricans between the ages of 15 and 26 years (mean 20.3). There were seven populations, two rural and five urban. The overall antibody prevalence was 61.4%. Because antibody prevalence was 57.1% in the 14 people who ate raw meat, and 61.6% in the 294 people who consumed raw eggs, meat and eggs could be excluded as important modes of transmission. We ascertained the presence of cats, type of soil contact, and flooring in the kitchen for every residence in which each individual lived from birth until interviewed. The 66% of people who indicated contact with cats had an antibody prevalence of 64%, and those without contact 56% (P = 0.02). In six of the seven populations, we found a positive correlation between cat contact and antibody prevalence; hence these six were studied together, and San Ramon, with a negative correlation, was examined separately. In the San Jose metropolitan population and in the total urban sample, cat contact was associated with a significantly higher antibody prevalence (P < 0.01). It was found that humans, even without acknowledged soil contact, acquire infection inside houses, especially with cement floors, when cats defecate in the house. Humans also acquire infection in or around houses with wooden floors, where the crawl space is an often unrecognized refuge of cats and a source of persistent soil contamination. San Ramon was the urban area with the highest human-cat contact (77%) and with the highest antibody prevalence in cats (75%). Although suggesting equal opportunities for infection, irrespective of cat contact, we cannot be certain in a retrospective study in which most of the infections took place an average of 15 years earlier. The most frequent antibody titer in our Costa Rican population was 1:1,024 (21%), much higher than the most frequent titers in a Colombian (1:64 to 1:128) and a U.S. population (1:16) of comparable age.

Worldwide reports of natural and experimentally-induced Toxoplasma gondii infections in cattle are reviewed and tabulated. Serologic tests employed in most studies in the past are of suboptimal sensitivity for the diagnosis of T. gondii infection in cattle; therefore data need to be interpreted with caution. From the evidence available it is concluded that: T. gondii is probably not important in causing abortion or clinical illness in cattle but further experimental studies are desirable; T. gondii is eliminated quickly from bovine tissues; Whether beef plays a part in the epidemiology of toxoplasmosis is unresolved; Milk from T. gondii-infected cows is of negligible importance in the epidemiology of toxoplasmosis.

Toxoplasma gondii was isolated from 3.5% of 202 Mus musculus, 12.5% of 120 Rattus norvegicus, 16% of 106 sparrows (Zonotrichia capensis), and from 54% of 50 chickens from Costa Rica. The infection rate in chickens increased from 23% in those weighing less than 500 g, to 73% in those between 500 and 1,000 g, indicating a rapid rate of acquiring infectin, probably from the soil in which they constantly search for food. No isolates were made from Musca domestica, or from four genera of roaches caught in the wild. However, Toxoplasma was isolated from four of 16 lots of earthworms. Most strains of Toxoplasma isolated from Costa Rican cats produced chronic latent infections in mice. However, even when infected with virulent strains, mice died at a time when numerous bradyzoites had been formed. Also, the availability of bradyzoites in chickens 8-10 days after ingestion of oocysts was comparable to that in mice. Therefore, several infected prey species are available as intermediate hosts to cats, providing the bradyzoites essential for the shedding of large numbers of oocysts. The isolation of Toxoplasma from earthworms or the soil associated with them illustrates their possible role as transport hosts to infect chickens and other birds feeding on them. The possible role of other transport hosts could not be confirmed.

Sixteen 1- to 7-week-old pregnant specific-pathogen free cats were inoculated orally with Toxoplasma gondii cysts. Fetuses and neonatal kittens were examined for toxoplasma infection by inoculating suspensions of their tissues into mice. Toxoplasma gondii was not isolated from 23 fetuses and 16 newborn kittens from 13 queens. Six (3 litters) of the 15 kittens from the 3 remaining queens were killed on the day of or a day after birth, and the remaining 9 kittens were housed with their mothers for 7 to 33 days. None of the 9 kittens from the 2 litters examined between 0 and 33 days of age was infected with T gondii. In the other litter, T gondii was isolated from 3 kittens killed at 9, 16, and 22 days of age but not from 3 littermates killed on days 1, 1, and 22. Internal organs from the 3 kittens with proved toxoplasma infectivity in mice were examined histologically. Multifocal granulomatous encephalitis, hepatitis, nephritis, myocarditis, myositis, and interstitial pneumonia were found in all 3 kittens. Toxoplasma forms were demonstrated histologically in the tissues of 2 of these kittens. The mode of toxoplasma infection in newborn kittens was not determined but did not appear to be either transplacental or via fecal contamination from oocysts excreted by the mother cat. Evidence obtained in these experiments suggests that transplacental toxoplasma infection in the cat is not an important epidemiologic factor in perpetuation of the disease in the feline population.

A farm in Illinois had swine with enzootic Toxoplasma gondii infections. Ninety-five of 99 pigs had antibody against T gondii by the modified agglutination test; modified agglutination test titers were less than 1:10 (4 pigs), 1:10 (15 pigs), 1:20 (12 pigs), 1:40 (10 pigs), 1:80 (20 pigs), 1:160 (11 pigs), 1:320 (12 pigs), 1:640 (9 pigs), and greater than or equal to 1:1,280 (6 pigs). To trace the route of infection, Toxoplasma-free pigs were introduced into the farm and were evaluated serologically at various intervals. Analysis of data derived from these tracer pigs indicated that cannibalism was a major source of T gondii infection in the pigs.

Six dogs inoculated with the GT-1 strain of Toxoplasma gondii aborted or gave birth to kids transplacentally infected with T gondii. In the next breeding season, does were bred to a T gondii-negative buck. Four of the 6 does gave birth to kids not infected with T gondii. At 139 days after breeding, 1 doe gave birth to 3 kids infected with T gondii. Kid 1 was born alive but died within 1 hour of birth; kid 2 was born dead; and kid 3 was born weak then euthanatized 1 day after birth. Toxoplasma gondii was isolated from fetal cotyledons and brain, heart, lung, liver, thigh muscle, and spinal cord of each kid. Microscopically, evidence of interstitial nodular pneumonia, hepatic necrosis, nonsuppurative myositis, myocarditis, and encephalitis was found in each kid. The 6th doe aborted 2 disintegrated fetuses at about 3 months of gestation.

A random sample representing approx. one-third of pre-school children and approx. 95% of school children in age groups 8, 11, 13, and 15 years in a suburb of Stockholm were examined for antibodies to Toxoplasma. Antibodies were uncommon in small children. They gradually appeared throughout childhood but especially in adolescence and adult life. Antibodies were more common in females than in males. Even small girls were more often infected than boys of corresponding age. The difference becomes marked in puberty and is significant in adults. A family study revealed evidence of familial aggregation of the infection albeit with borderline significance. No correlation was found between occurrence of antibodies and the presence of cats in the families or reported consumption of raw meat. The majority of representative samples of Lapps and Skolt Lapps in northern Scandinavia lacked antibodies to Toxoplasma.

Two of three litter-mate kittens born to an Abyssinian cat died of acute toxoplasmosis. Toxoplasma gondii was found in histologic sections of both kittens and this was confirmed by immunoperoxidase staining.

Three hundred and ninety patients with suspected toxoplasmosis due to their contact with animales--they owned them, or work with them--are studied. The great significance of this way of acquiring the disease is stated. Every patient had a complement fixation test and an intradermal reaction test with toxoplasmine. An 85.2% positiveness to complement fixation, and a 64.1% to intradermal test were found among those patients who informed animal contact; a 70,6% positiveness to complement fixation, and a 56,2% to intradermal reaction was found in the patients who denied having any contact with animals. This showed both the importance of animal contact as well as other forms of transmission. The contacts were also studied, and the animals were classified according to J. Jira, the researcher: maximal, high, minimal and unreceptiveness to toxoplasma. The possibility of acquiring toxoplasmosis from other sources besides the close contact with animals must be taken into consideration.