Cryptosporidiosis of man and calf: a case report and results of experimental infections in mice and rats.

Cryptosporidiosis is reported in a healthy 25-year-old male. Clinical symptoms include 1 day of nausea and low-grade fever and 9 days of diarrhea, followed by 3 days of constipation. Oocysts of Cryptosporidium sp. were present in sugar flotations of the first fecal sample collected 56 hours after onset of the symptoms and in daily fecal samples collected through day 12 of the illness. Oocysts of the human isolate of Cryptosporidium sp. were morphologically indistinguishable from those obtained from naturally and experimentally infected calves. After 1 week of sporulation at room temperature, oocysts from the human and from calves contained four sporozoites and a spherical residuum. When inoculated orally, sporulated Cryptosporidium sp. oocysts of human and of calf origin produced indistinguishable infections in suckling mice and rats and in adult mice.

Filaroides hirthi in a dog: fatal hyperinfection suggestive of autoinfection.

Progressive dyspnea in a dog began 1 month after it had been hit by a car. Radiographs revealed diffuse interstitial and alveolar pneumonia. Large numbers of embryonated eggs were observed in bronchial washings; and many small nematodes, later identified as Filaroides hirthi, were found in the fine needle aspirates of pulmonary tissue. Numerous nematode larvae were demonstrated on fecal flotation. The severe hyperinfection strongly suggested autoinfection, probably associated with depressed immunologic competence due to chronic stress.

Diagnosis and treatment of peritonitis caused by a larval cestode Mesocestoides spp., in a dog.

Infection of the peritoneal cavity with cestode larvae, presumptively diagnosed as tetrathyridia of the genus Mesocestoides, was found by exploratory celiotomy in a dog with clinical signs consisting of episodic anorexia, vomiting, and depression. Lymphopenia and hypoalbuminemia were associated clinicopathologic abnormalities. Dystrophic calcification and midline duodenal displacement were found on abdominal radiographs. Therapy with mebendazole was instituted after recurrence of the initial episodic clinical signs postoperatively. Daily use of mebendazole for intermittent periods of up to 3 months led to remission of gastrointestinal signs for 30 months. However, 17 months after the initial diagnosis, infection of the vaginal tunic of the testicle with similar cestode larvae necessitated castration and removal of the vaginal tunic to the inguinal ring. Mebendazole therapy was reinstituted and continued for 31/2 months postoperatively. The dog was free of clinical signs of infection during and for the 16 months since this period of treatment.

Human cryptosporidiosis in immunocompetent and immunodeficient persons. Studies of an outbreak and experimental transmission.

Infection with cryptosporidium occurred in 12 immunocompetent persons who had direct contact with the feces of infected calves during three unrelated outbreaks of calf cryptosporidiosis. Nine of the twelve subjects had diarrhea and abdominal cramps that lasted 1 to 10 days. Infections were diagnosed and monitored by detection of oocysts in feces, with a modified Sheather's flotation technique and phase-contrast microscopy. Oocysts of cryptosporidium were isolated from calves but not from other animals with which these subjects had been in contact. Oocysts of cryptosporidium were also detected during repeated examinations of feces from two immunodeficient patients with persistent cryptosporidiosis. An apparently identical infection was transmitted to calves and mice, using oocysts from infected calves and human beings. Oocysts from an immunodeficient person also produced infections in kittens, puppies, and goats. This study shows that cryptosporidium may produce a moderate self-limited illness in immunocompetent persons, which contrasts sharply with the prolonged severe diarrhea in immunocompromised patients who contract cryptosporidiosis. Calves with diarrhea should be considered a potential source of human infection, and immunocompromised persons should avoid contact with such animals.