Cryptosporidium infections associated with swimming pools--Dane County, Wisconsin, 1993

In March and April 1993, an outbreak of cryptosporidiosis in Milwaukee resulted in diarrheal illness in an estimated 403,000 persons (1). Following that outbreak, testing for Cryptosporidium in persons with diarrhea increased substantially in some areas of Wisconsin; by August 1, 1993, three of six clinical laboratories in Dane County were testing routinely for Cryptosporidium as part of ova and parasite examinations. In late August 1993, the Madison Department of Public Health and the Dane County Public Health Division identified two clusters of persons with laboratory-confirmed Cryptosporidium infection in Dane County (approximately 80 miles west of Milwaukee). This report summarizes the outbreak investigations.

Emerging infectious diseases in the United States, 1993

Three outbreaks of disease in the United States in 1993 caused by Escherichia coli O157:H7, Cryptosporidium organisms, and a previously unrecognized hantavirus clearly illustrate the increasing challenges posed by emerging infectious diseases. The largest US outbreak of E. coli O157:H7 infection reported occurred as a result of contaminated hamburgers served at a fast-food restaurant chain. The largest recorded waterborne disease outbreak in US history was due to contamination of a municipal water supply with cryptosporidia. In the southwestern United States, hantavirus was first recognized as the cause of a pulmonary syndrome with a mortality rate exceeding 50%. The detection of and response to these outbreaks document the need for a strong partnership between the clinical and public health sectors to prevent and control diseases. Health care reform in the United States provides an opportunity to address critical needs, such as improved surveillance and diagnosis, to ensure timely detection of and rapid response to newly emerging infectious diseases.

Susceptibility of major histocompatibility complex (MHC) class I- and MHC class II-deficient mice to Cryptosporidium parvum infection

Major histocompatibility complex (MHC) class I-deficient and MHC class II-deficient mice lack functional CD8 T cells and CD4 T cells, respectively. These mice were evaluated for infection following oral administration of 10(7) Cryptosporidium parvum oocysts. MHC class II-deficient (but not MHC class I-deficient) mice dosed with C. parvum oocysts at 3 to 5 days of age remained infected 8 weeks postexposure. MHC class II-deficient mice exposed to C. parvum oocysts at 5 to 6 weeks of age were significantly more susceptible to infection than control mice (P < 0.0001).

Surveillance for waterborne disease outbreaks--United States, 1991-1992

PROBLEM/CONDITION

Since 1971, CDC and the U.S. Environmental Protection Agency have maintained a collaborative surveillance program for collection and periodic reporting of data on the occurrence and causes of waterborne disease outbreaks.

REPORTING PERIOD COVERED

January 1991 through December 1992.

DESCRIPTION OF SYSTEM

The surveillance system includes data about outbreaks associated with water intended for drinking and also about those associated with recreational water. State and local public health departments are the agencies with primary responsibility for the detection and investigation of outbreaks. State and territorial health departments report these outbreaks to CDC on a standard form.

RESULTS

For the 2-year period 1991-1992, 17 states and territories reported 34 outbreaks associated with water intended for drinking. The outbreaks caused an estimated 17,464 persons to become ill. A protozoal parasite (Giardia lamblia or Cryptosporidium) was identified as the etiologic agent for seven of the 11 outbreaks for which an agent was determined. Five (71%) of the outbreaks caused by protozoa were associated with a surface-influenced groundwater source. One outbreak of cryptosporidiosis was associated with filtered and chlorinated surface water. Shigella sonnei and hepatitis A virus were implicated in one outbreak each; both were linked to consumption of contaminated well water. Two outbreaks due to acute chemical poisoning were reported; one had an associated fatality. No etiology was established for 23 (68%) of the 34 outbreaks, including the largest one reported during this period, in which an estimated 9,847 persons using a filtered surface water supply developed gastroenteritis. Most (76%) of the 34 outbreaks were associated with a well water source. Twenty-one states reported 39 outbreaks associated with recreational water, in which an estimated 1,825 persons became ill. The most frequently reported illness was hot tub- or whirlpool-associated Pseudomonas dermatitis (12 outbreaks). Of 11 outbreaks of swimming-associated gastroenteritis, six were caused by Giardia or Cryptosporidium, including three outbreaks associated with chlorinated, filtered pool water. The first reported outbreak of Escherichia coli O157:H7 infection associated with recreational exposure occurred during this period. Primary amebic meningoencephalitis, caused by Naegleria fowleri infection, resulted in six deaths.

INTERPRETATION

The number of waterborne disease outbreaks reported per year has not changed substantially in the past 5 years. However, etiologic agents only recently associated with waterborne disease, such as E. coli O157:H7 and Cryptosporidium, are being reported more frequently and from new settings. Water quality data for outbreaks during the period 1991-1992 indicate that available water disinfection technology is not always in place or used reliably.(ABSTRACT TRUNCATED AT 400 WORDS)

Dose response of Cryptosporidium parvum in outbred neonatal CD-1 mice

Cryptosporidium parvum infectivity in a neonatal CD-1 mouse model was used to determine the dose needed to infect 50% of the population. The 50% infective dose was estimated to be 79 oocysts. It was observed that a mean oral inoculum of 23 oocysts produced infection in 2 of 25 neonatal mice 7 days postinoculation. All animals became infected when the mean oral dose exceeded 310 oocysts per animal. The dose response of C. parvum was modeled with a logit dose-response model suitable for use in water disinfection studies.

The prevalence of cryptosporidiosis in children and adults at University Hospital, Kuala Lumpur

A total of 320 faecal specimens obtained from 295 patients (192 children and 103 adults) with diarrhoea and 47 faecal specimens from healthy adults were screened for Cryptosporidium oocysts. Faecal specimens were first screened by modified Ziehl Neelsen stain and specimens with oocysts were confirmed by direct immunofluorescence technique. Cryptosporidium oocysts were detected in 4 children but not in normal healthy adults or in diarrhoeic adults.

Environmental sources of Cryptosporidium in an urban slum in northeastern Brazil

Cryptosporidium is an important cause of diarrheal disease in children worldwide. To elucidate the environmental sources of this parasite, we selected an urban slum in Fortaleza, Brazil, a community with a known high incidence of cryptosporidiosis, and examined both stool smears from household animals (n = 127) and filtrates from local water sources (n = 18) for Cryptosporidium oocysts. Because previous work in this community has demonstrated the seasonal nature of human infection with Cryptosporidium, collections were made separately for the dry and rainy seasons. Of the 64 stools collected during the dry season (September-December 1990), four (6.3%) were positive by acid-fast staining for Cryptosporidium. Of the 63 rainy season samples (March-May 1991), nine (14.3%) were positive. Overall, oocysts were detected in 13 (10.2%) of 127 animal stool samples. Freshwater samples were obtained from a variety of sources including open and closed wells, and running city water and then processed. Four of 18 samples (22.2%), including a sample from city water were positive by at least one of two staining techniques (acid-fast and immunofluorescence). In summary, animals may serve as a reservoir of Cryptosporidium, with potential for the contamination of immediate household water sources. These findings may help to explain the high incidence of cryptosporidiosis among infants in this impoverished community.

Correlation of circulating antibody and cellular immunity with resistance against Cryptosporidium baileyi in broiler chickens

The correlation of circulating antibody and cell-mediated immunity (CMI) with resistance to Cryptosporidium baileyi was studied using hormonal and chemical bursectomy in the one experiment and cyclosporin A in a second experiment. In Expt. 1, there was no correlation between antibody (confirmed by enzyme-linked immunosorbent assay) and resistance to infection as measured by body weight, gross lesions, morbidity, and mortality. Bursectomy altered antibody production, but not CMI, as measured by the delayed-type hypersensitivity skin reaction. In Expt. 2, cyclosporin A reduced CMI, but not antibody production. Chicks treated with cyclosporin A were more susceptible to C. baileyi (more severe respiratory disease) than untreated controls. Results suggested that CMI is more important in resistance to C. baileyi than circulating antibody.

Azithromycin for treatment of severe Cryptosporidium diarrhea in two children with cancer

Two children with cancer received azithromycin for Cryptosporidium-associated diarrhea that was unresponsive to supportive care. One child had choleriform diarrhea requiring daily fluid replacement of up to 65% of his total body weight; the other had protracted diarrhea and wasting. In both cases, administration of azithromycin was followed by prompt clinical improvement.

AIDS-related cholangiopathy. Critical analysis of a prospective series of 26 patients

Several types of biliary tract abnormality of undetermined origin have been described among AIDS patients. The aims of this study are: (1) to evaluate whether biliary tree involvement is in fact one or several homogeneous morphological entities, (2) to specify the role of CMV or Cryptosporidium sp. infection, and (3) to evaluate the possible efficacy of treatment. Since ultrasound had revealed abnormality in the biliary tree, 26 consecutive AIDS patients underwent cholangiography. Cholangiograms enabled us to distinguish between two types of biliary tract involvement: (1) gradual and regular stenosis of the terminal portion of the common bile duct associated with dilation but without irregularity of the intrahepatic biliary ducts was present in 27% of our cases, and (2) distal stenosis of the extrahepatic biliary ducts combined with diffuse irregularity of the caliber of the intrahepatic bile ducts was present in 73% of our cases. Concomitant infection by CMV or Cryptosporidium sp. was significantly more frequent when intrahepatic duct irregularities were present (94%) than when absent (14%, P < 0.001). Anti-CMV treatment and sphincterotomy were unsuccessful in treating anomalies of the intrahepatic biliary tract. Conversely, sphincterotomy caused rapid and lasting disappearance of pain in all our patients. In conclusion, biliary tract involvement in AIDS patients is of two types. CMV infection and infection by Cryptosporidium sp. are most frequent when the large intrahepatic ducts are implicated.

Cryptosporidiosis in patients infected with the human immunodeficiency virus

Infection caused by Cryptosporidium species has proved to be one of the most taxing and frustrating conditions faced by clinicians caring for patients with AIDS. Unfortunately, this unique organism, which was identified as a human pathogen only shortly before the AIDS epidemic began to manifest itself, has received only minimal attention during the past decade. Dr. Carolyn Petersen, an assistant professor of medicine at the University of California, San Francisco, and a member of the Division of Infectious Diseases at San Francisco General Hospital, is a molecular parasitologist whose investigative career is focused on elucidating the biology of Cryptosporidium species. In this AIDS Commentary Dr. Petersen provides an update on recent developments in this field.

Vapreotide, a somatostatin analogue, in cryptosporidiosis and other AIDS-related diarrhoeal diseases

OBJECTIVE

To evaluate the efficacy and tolerance of vapreotide, a new somatostatin analogue, in the treatment of refractory AIDS-related diarrhoea.

DESIGN

An open, non-comparative pilot trial.

SETTING

The trial was conducted in 10 medical centres in France.

PATIENTS, PARTICIPANTS

Thirty-four AIDS patients with chronic diarrhoea unresponsive to conventional antidiarrhoeal therapy were enrolled. Cryptosporidiosis was diagnosed in 21 out of 30 evaluable patients. Mean number of stools prior to therapy was 10.1 +/- 4.9 per day (range, 3-20 stools per day).

INTERVENTION

After initial baseline studies, patients received subcutaneous vapreotide at escalating doses of 400 (23 patients) or 500 micrograms (seven patients), between two and six times daily.

MAIN OUTCOME MEASURES

Efficacy was assessed after 14 days of therapy, when it was found to be effective. Responders were offered the opportunity to continue receiving therapy.

RESULTS

Four patients demonstrated a complete response and 12 a partial response with greater than 50% reduction in daily stool emission. Fourteen patients did not respond to doses up to 2400 micrograms/day. Patients with conditions other than cryptosporidiosis had a significantly higher probability of response (P = 0.013), as did those with milder diarrhoea (less than 10 stools per day). Median duration of response was 1.5 months (range, 0.5-5 months); relapse occurred in five out of eight responders despite maintenance therapy. Toxicity was minimal.

CONCLUSIONS

We conclude that AIDS patients with diarrhoea not caused by Cryptosporidium may benefit from vapreotide therapy.

Pathogenesis of intestinal cryptosporidiosis in conventional and gnotobiotic piglets

The pathogenesis of intestinal cryptosporidiosis was studied in 52 conventionally reared and 20 gnotobiotically reared piglets by inoculation with different doses of Cryptosporidium parvum oocysts. The prepatent period of C. parvum in both groups of animals were variable, depending on the number of oocysts administered. The patent period of C. parvum in conventionally reared piglets was 8 or 9 days; in gnotobiotic piglets cryptosporidia were found in feces until Day post infection (DPI) 16, when the last piglet was necropsied. Cryptosporidiosis in conventionally reared piglets is a self-limited diarrheal disease associated with morphological changes within the intestine. The most severe lesion was seen in the posterior jejunum and ileum from DPI 3 to DPI 7, and consisted of villous atrophy, crypt hyperplasia and inflammatory infiltration in the lamina propria. In gnotobiotic piglets cryptosporidia induced severe enterocolitis which occurred at least until DPI 16. The characteristics of enteric lesions were similar to those found in conventionally reared piglets. Intestinal cryptosporidiosis in both groups of animals shifted in the course of infection in the caudal direction and terminated in the large intestine. Examination by scanning electron microscope showed that infected absorptive cells had thicker and longer microvilli than those on non-infected cells; neighboring non-infected cells were hypertrophic, bulbously protuberant with minute microvilli with no distinct intercellular borders. Numerous cryptosporidia in the heterotopic glandular epithelium in the submucosa of cecum and colon on DPI 9 and 10 were found. No differences in the location and degree of cryptosporidial infection between colostrum-fed and colostrum-deprived conventionally reared piglets were found. Sow's colostrum does not appear to protect piglets from C. parvum infection. The role of intestinal microflora in the pathogenesis of cryptosporidiosis in piglets is discussed.

An outbreak of cryptosporidiosis associated with a swimming pool

In August 1988 an increase was noted in the number of cases of cryptosporidiosis identified by the microbiology laboratory at Doncaster Royal Infirmary. By 31 October, 67 cases had been reported. Preliminary investigations implicated the use of one of two swimming pools at a local sports centre and oocysts were identified in the pool water. Inspection of the pool revealed significant plumbing defects which had allowed ingress of sewage from the main sewer into the circulating pool water. Epidemiological investigation confirmed an association between head immersion and illness. The pools were closed when oocysts were identified in the water and extensive cleaning and repair work was undertaken. The pool water was retested for cryptosporidial oocysts and found to be negative before the pool reopened.

The prognosis in HIV-infected patients with pneumonia. Relation to microbiological diagnoses

Ninety consecutive first-time fiberoptic bronchoscopies (FB) were performed on HIV-infected patients with pulmonary symptoms and radiographic evidence of active pneumonitis. Microbiological data were analysed for acute and long-term prognostic significance. 56/90 (63%) patients had one type of microbiological agent recovered from FB, 22/90 (24%) patients had more types recovered, and 12/90 (13%) patients had no types recovered. Nine patients (10%) died during the acute episode of pneumonia. A prognostic factor of a fatal outcome of the acute episode of pneumonia was concurrent multiple pulmonary infections (p = 0.002), mainly ascribed to patients with Pneumocystis carinii pneumonia (PCP) and concomitant bacterial pneumonia (p = 0.003). Specific microbiological findings at FB did not influence long-term survival of patients, and, when omitting patients who died during the acute episode of pneumonia (n = 9), no difference in survival was observed between patients with a) no agent, b) one type of agent or c) more types of agents recovered from FB. Only non-pulmonary parameters such as CD4-count, haemoglobin and age were found to be prognostic parameters. Thus, increased attention should be paid to co-pathogens presenting in HIV-infected patients with pulmonary infection and appropriate therapy instituted.

Cryptosporidiosis

Data suggest that C. parvum is now one of the three most commonly found enteropathogens causing diarrheal illness in humans worldwide. This article discusses the etiologic agents, epidemiology, clinical features, diagnosis, and treatment of cryptosporidiosis. To date, no effective therapy for cryptosporidiosis has been identified.

An outbreak of waterborne cryptosporidiosis in Swindon and Oxfordshire

An outbreak of cryptosporidiosis resulted in 516 cases in Wiltshire and Oxfordshire. The outbreak caused widespread interest and led to an official inquiry. The majority of cases were in children; 8% of cases were admitted to hospital and the median duration of illness was 3 weeks. The geographical distribution of cases matched the distribution of water supplies from three treatment works and cryptosporidium oocysts were found at these works and in the treated water. Attack rates in electoral wards supplied by the three treatment works were significantly higher than in other wards. The cause of the outbreak appeared to be the failure of normal treatment to remove oocysts. Measures at the treatment works reduced the number of oocysts detected in treated water, after which the outbreak came to an end. The conclusion of the investigations was that cryptosporidiosis is a risk of conventionally treated public water supplies.

A comparative study on the biology of Cryptosporidium sp. from guinea pigs and Cryptosporidium parvum (Apicomplexa)

Cryptosporidium sp. from guinea pigs and C. parvum were compared morphologically, electrophoretically, and for the ability to infect suckling mice. Oocysts from guinea pigs measured 5.4 x 4.6 (4.8-5.6 x 4.0-5.0) microns and had a shape index (length/width) of 1.17 (1.04-1.33). Oocysts of C. parvum were similar and measured 5.2 x 4.6 (4.8-5.6 x 4.2-4.8) microns with a shape index of 1.16 (1.04-1.33). All suckling mice inoculated with oocysts of C. parvum became infected, whereas most, but not all, mice fed oocysts of the guinea pig isolate also became infected. However, mice inoculated with oocysts from guinea pigs produced on average 100-fold fewer oocysts by day 7 postinoculation than did mice infected with C. parvum, and the resulting infections were sparse and patchy along the ileum. Electrophoretic profiles were similar, but 125I surface labeling of outer oocyst wall proteins revealed striking differences between the two isolates. Cryptosporidium parvum had a wide molecular size range of 125I-labeled bands, whereas C. sp. from guinea pigs had a banding pattern clustered between 39 and 66 kDa, with a smaller number of bands greater than 100 kDa.

Cryptosporidiosis in the Isle of Thanet; an outbreak associated with local drinking water

An outbreak of cryptosporidiosis occurred in the Isle of Thanet during December 1990 and January 1991. A total of 47 cases ranging in age from 2 months to 85 years were identified in residents from the Margate, Broadstairs and Ramsgate areas, with dates of onset of illness from 3 December to 14 January. A case-control study demonstrated a strong statistical association between illness and the consumption of unboiled tap water from a particular source, with evidence of a dose-response relationship. Although no cryptosporidial oocysts were identified in samples of untreated or treated water taken during the investigation, the results were consistent with the view that the source of infection was treated river water which was used to supplement borehole water.

[Cryptosporidium diarrhea developing in two Japanese adults--one in AIDS and the other in a normal host. Research Group for Infectious Enteric Diseases, Japan]

Case I: A middle-age homosexual male developed AIDS with Pneumocystis carinii pneumonia (PCP) and esophageal candidiasis in 1986 during his stay in an European country about five months prior to transfer to Tokyo Metropolitan Komagome Hospital, Tokyo, in 1987. He was also diagnosed as having cryptosporidiosis presenting with mild diarrhea a month following the diagnosis of PCP. Diarrhea was successfully treated with spiramycin. On transfer to Tokyo Metropolitan Komagome Hospital, he was febrile but had no diarrhea. Serum HIV and TPHA were positive and his blood lymphocyte subset T4a was markedly decreased. On the 13th day after transfer to the hospital, watery diarrhea appeared. Cryptosporidium oocysts were detected from the feces taken on the 17th hospital day. The patient died of Escherichia coli septicemia on the 38th hospital day. Autopsy finding yielded Cryptosporidium infection widely spread over the stomach, ileum, bile and pancreatic ducts. Case II: A 31-year-old previously healthy female presented with abrupt onset of mucous stool five times daily. Mucous passage continued on the subsequent days despite administration of loperamide, and the passage increased to 20 times daily with mucous to watery diarrhea associated with mild abdominal cramps and nausea on the 4th day after onset of illness. On the 6th day of illness, she visited Tokyo Metropolitan Komagome Hospital. She denied close contact with pet animals or contact with any person presenting diarrhea. She had no recent history of travelling anywhere outside Tokyo. On examination she was an apparently healthy woman except for a slightly distended abdomen with localized tenderness in the right upper quadrant.(ABSTRACT TRUNCATED AT 250 WORDS)

Respiratory and enteric cryptosporidiosis in humans

A 24-year-old homosexual man with acquired immunodeficiency syndrome presented with intractable diarrhea and fever. Examination of a rectal biopsy specimen and stool revealed Cryptosporidium. Approximately 4 months after admission he developed respiratory failure and died. Postmortem examination revealed cryptosporidiosis involving the entire gastrointestinal tract as well as the tracheobronchial tree. To our knowledge, this is one of the rare presented cases of tracheobronchial cryptosporidiosis documented histologically.

Persistent cryptosporidiosis in horses with severe combined immunodeficiency

Cryptosporidial infections were established in five young foals with severe combined immunodeficiency following oral administration of 10(8) Cryptosporidium parvum oocysts. All foals shed oocysts (average of 8 x 10(6) to 2 x 10(8)/g of feces) until death. Inflammation and C. parvum organisms were observed in the common bile duct, duodenum, jejunum, and ileum. Since foals with severe combined immunodeficiency lack functional T and B lymphocytes and are incapable of antigen-specific immune responses, they are well suited for evaluating the pathogenesis and treatment of persistent cryptosporidiosis.

Cryptosporidiosis in patients with hematologic malignancies

The clinical features of cryptosporidial infection in 20 patients with hematologic malignancies were assessed. Five patients had severe diarrhea, 10 had moderate diarrhea, and five were asymptomatic carriers of Cryptosporidium. Extraintestinal cryptosporidiosis with pulmonary involvement was observed in one case and relapse of cryptosporidiosis in four. All but one patient recovered from cryptosporidiosis whether or not spiramycin was administered. Cryptosporidiosis in T cell-depleted recipients of allogeneic bone marrow transplants did not appear more severe than that in patients undergoing autologous bone marrow transplantation or conventional chemotherapy.

The relationship of microbial pathogens to acute infectious diarrhoea of childhood

Bacterial, viral and parasitic enteric pathogens were detected in 692 of 916 children below 36 months of age with acute diarrhoea and in 289 of 587 matched controls. The rates of identification of only four groups of pathogens, rotavirus, Shigellae, Salmonella typhimurium and enterotoxigenic E. coli, were significantly higher in the patients. The prevalence of a variety of other enteric pathogens was similar in controls of patients. Shigellosis had a characteristic clinical profile but none of the other agents could be suspected on clinical grounds. The high prevalence of pathogens in controls suggested that the population may be partially protected against a variety of enteric pathogens and that final common pathways leading to diarrhoea may be activated by changes in the microbial ecology of the gut lumen.

Chronic Cryptosporidium parvum infections in congenitally immunodeficient SCID and nude mice

Severe combined immune deficient (SCID) and athymic National Institutes of Health (NIH)-III (bg/nu/xid) mice were evaluated for susceptibility to Cryptosporidium parvum infections as neonates and as adults after challenge with inocula of 5 x 10(4) and 1 x 10(6) oocysts/mouse, respectively. SCID and NIH-III nude mice developed chronic infections that persisted over 12 weeks. Cryptosporidial organisms were observed in the small and large intestines of all mice. Colonization of the gallbladder and hepatobiliary duct epithelium occurred in a majority of the NIH-III nude mice and a smaller number of the SCID mice. Severe infections in both mouse strains were associated with clinical deterioration followed by death. Signs in these mice included dehydration, icterus, and emaciation. Deaths apparently resulted from hepatic dysfunction. Control mice experienced transient infections with no clinical signs. Immunodeficient mice should prove useful in studies of disease pathogenesis and in evaluating potential anticryptosporidial agents.

Resolution of Cryptosporidium infection in an AIDS patient after improvement of nutritional and immune status with octreotide

An AIDS patient with severe large volume diarrhea and malnutrition due to cryptosporidial infection is presented. The patient, who was not receiving zidovudine, was treated with octreotide with resolution of diarrhea leading to improvement in nutritional status, immune functions, and subsequently, resolution of the Cryptosporidium infection. This case points out the need for adequate nutrition in AIDS patients and highlights the relationship of nutrition and the immune system.

Parasitic diseases. Diseases associated with acquired immunodeficiency syndrome

There are several protozoan infections that cause relatively benign illness in normal individuals but result in severe disease manifestations in patients with AIDS. These diseases include Pneumocystis carinii pneumonia, CNS toxoplasmosis, cryptosporidiosis, and isosporiasis. Pneumocystis carinii pneumonia (PCP) caused by Pneumocystis carinii, is the most common opportunistic infection in AIDS. It is seen in more than 80% of individuals with this syndrome. Although historically classified as a protozoan, this organism shares many biochemical characteristics with fungi. The onset of PCP may be insidious, and cough and dyspnea are the most common presenting symptoms. Auscultation of the lungs is often unremarkable, but diffuse infiltrates are commonly seen on chest radiographs. The diagnosis of PCP can be confirmed by identifying the organism on specimens obtained by sputum induction or bronchoalveolar lavage. Trimethaprim-sulfamethoxazole is the treatment of choice but is unfortunately associated with leukopenia and rash in many individuals. Both trimethaprim-sulfamethoxazole and aerosolized pentamidine are used prophylactically in patients at high risk for initial or relapsing infection. The appropriate use of these agents has resulted in improved survival for AIDS patients with PCP. Toxoplasmosis, due to Toxoplasma gondii, affects the central nervous system in patients with AIDS. Headache is a common presenting symptom, and both seizures and paresis can occur. A diagnosis of toxoplasmosis is strongly suspected in symptomatic individuals with ringed mass lesions noted on head CT. Patients with this condition are treated with a combination of sulfadiazine, pyrimethamine, and folinic acid. Cryptosporidiosis and isosporiasis are coccidian protozoan diseases that can result in severe, acute, and chronic diarrhea in immunocompromised individuals. Cryptosporidiosis is the more common of the two and is caused by an unknown species of the genus crytosporidium. Isosporiasis is due to infection with Isospora belli. Dehydration and weight loss are a common result of infection with either agent. A definitive diagnosis can be made by examining an acid fast stain of a diarrheal stool specimen and demonstrating oocysts that are specific for each of these organisms. Fluid replacement and general supportive care are essential in the treatment of both of these diseases. Spiramycin is an unproven treatment modality that is often used in patients with cryptosporidiosis. Isosporiasis responds to initial therapy with trimethaprim-sulfamethoxazole, followed by prophylaxis with pyrimethamine. The adoption of safe sexual practices that minimize fecal-oral contamination should decrease the future prevalence of these diseases and other enteric parasitic infections.

Cryptosporidium infection in acquired immunodeficiency syndrome: not always a poor prognosis

Chronic diarrhea and malabsorption accompanied by simultaneous infection with the protozoa Giardia lamblia and Cryptosporidium occurred in a 22-year-old homosexual man with antibody to human immunodeficiency virus (HIV). Small bowel biopsy demonstrated total villous atrophy and marked mononuclear infiltration in the lamina propria simulating celiac disease. Treatment with metronidazole resulted in resolution of diarrhea, clearance of parasites, and marked improvement in small bowel histology. Although diarrhea and malabsorption in immunocompromised patients with cryptosporidiosis are regarded as ominous, our patient remained disease free for the next 3 years. Thus, infection with Cryptosporidium in patients with HIV does not always lead to intractable diarrhea or death.

In vitro cultivation of Cryptosporidium parvum and screening for anticryptosporidial drugs

Sporozoites of Cryptosporidium parvum which were excysted in vitro from oocysts isolated from calves or patients with acquired immune deficiency syndrome underwent development in monolayers of the mouse fibroblast cell line L929. Asexual multiplication occurred, with the maximum numbers of parasites usually being observed between 24 and 48 h after infection. Gametocytes were also found, but their numbers were relatively small compared with those of the asexual stages. A study was made of the effect on parasite development of 20 antimicrobial agents, most of which were anticoccidial or antimalarial agents. The majority of the drugs had a limited inhibitory effect on parasite development, but usually only at high concentrations. The two most active drugs were monensin and halofuginone, which reduced parasite multiplication by more than 90% at high concentrations. In the case of monensin, however, inhibition of parasite development at higher concentrations was due, at least in part, to a toxic effect of the drug on the host cells.

A probable waterborne outbreak of cryptosporidiosis in the Sheffield area

There was a marked peak in human cases of cryptosporidiosis in the Sheffield area in May and June 1986. Extensive epidemiological investigations failed to find a common source of food or a consistent history of animal contact, but did suggest that a waterborne outbreak of cryptosporidiosis may have occurred. Cryptosporidium oocysts were found in untreated water and in fish from a reservoir complex implicated by epidemiological analysis. Laboratory investigations confirmed that cattle on a farm adjacent to the reservoir complex were a possible source of contamination.

Cryptosporidiosis and AIDS

Cryptosporidiosis in patients with AIDS presents as a chronic enteritis, with biliary complications in about 10% of sufferers. The disease is persistent and progressively fatal. Due to the widespread prevalence of the parasite in the community and amongst domesticated animals, persons with AIDS are constantly at risk. Treatment is extremely difficult in view of the apparent lack of a specific anticryptosporidial drug. Methods of immunomodulation are worth considering, but the main recourse may have to be a prolonged regimen of rehydration and parenteral nutrition. However, if T helper cell function improves, the disease may go into remission or the parasite could be eliminated. Vaccination of those at risk is not feasible at present.

Intestinal cryptosporidiosis acquired from a cat

A case of intestinal cryptosporidiosis in an eight-year-old boy is presented. The patient became ill during a visit to a farm where diarrhoea in newborn calves is a recurrent problem. Furthermore, on that farm kittens periodically suffer from diarrhoea and failure to thrive. Oocysts of Cryptosporidium sp. were identified in the stool of the patient, and in the stool of the cat he had contact with. At that time the calves were not infected. The patient's gastrointestinal symptomatology consisted of severe diarrhoea, vomiting, colics and moderate dehydration, and was preceded by coughing.

[Experimental activation of cryptosporidiosis in mice by immunosuppression]

Cryptosporidium, a coccidian parasite first described by Tyzzer (1907) from a laboratory mouse, has become an important human enteric pathogen causing overwhelming diarrhea especially in immunocompromised patients such as AIDS. This parasite has been reported from over 20 countries and is recognized as a cosmopolitan species. In Korea, however, there has been no report on human as well as animal cryptosporidiosis. This study was performed so as to verify the presence of Cryptosporidium in Korea by activating the parasite from laboratory mice by immunosuppression. Total 65 conventionally-bred ICR mice including a control (5 mice) and 3 experimental groups (20 each) were used for this study. Group I was immunosuppressed with prednisolone injection (1 mg IM, every other day) for 7 weeks. Group II (prednisolone injection and tetracycline administration) and Group III (prednisolone injection and trimethoprim-sulfamethoxazole administration) were prepared to observe the effect of antibacterial agents on the activation of cryptosporidiosis. In fecal examinations of mice Cryptosporidium oocysts (4-6 microns in size) were detected from 1 week after the start of immunosuppression and the mice began to die. In H-E stained tissue sections of the lower jejunum, numerous very small (2-4 microns), dense, ovoid or spherical, slightly basophilic bodies were seen attached on the free border of mucosal epithelial cells. In scanning and transmission electron microscopic observations, these organisms were identified as various developmental stages of Cryptosporidium. The species is considered to be C. parvum.(ABSTRACT TRUNCATED AT 250 WORDS)

Experimental cryptosporidiosis in hamsters

A new laboratory animal model for experimental cryptosporidiosis is described. Adult immunosuppressed hamsters were infected per os with 0.5 x 10(5) and 1 x 10(5) Cryptosporidium oocysts of calf origin. The mean numbers of oocysts shed per gram of feces per day and the patterns of infection are described. The susceptibility to Cryptosporidium infection, the total number of oocysts shed (a thousand times the infective dose), and the ease of handling in laboratory conditions make hamsters a good animal model for cryptosporidiosis.

An outbreak of waterborne cryptosporidiosis caused by post-treatment contamination

An outbreak of waterborne cryptosporidiosis affecting 27 persons, diagnosed stool positive, occurred in Ayrshire in April 1988. Twenty-one in 27 confirmed cases required some form of fluid replacement therapy. Local general practitioners indicated a two- to fivefold increase in diarrhoeal disease during the outbreak, and following enquiries made by Environmental Health Officers it became apparent that many hundreds of people had suffered a diarrhoeal illness at that time. Cryptosporidium spp. oocysts were detected in the treated chlorinated water supply system, in the absence of faecal bacterial indicators. Oocyst contamination of a break-pressure tank containing final water for distribution was the cause of this waterborne outbreak. An irregular seepage of oocyst-containing water, which increased during heavy rains, was the cause of the break-pressure tank contamination, rather than a failure of the water-treatment processes. The waterborne route should be considered when clusters of cryptosporidiosis-associated with potable water occur. Waterborne cryptosporidiosis can occur in the absence of other faecal indicators of contamination.

[Incidence of Cryptosporidium sp in patients treated in a general hospital. Technics for the identification of oocysts in feces]

In feces referred for parasite investigation from 1973 patients of the Hospital Clinico Universitario in Salamanca, 27 instances of infestation by Cryptosporidium sp (1.5% of all investigated patients) were detected in 19 children (1.4%) and 8 adults (2.2%). The incidence in patients with antibodies against the human immunodeficiency virus (HIV) was 12.5%, in contrast with 1.25% in patients without anti-HIV antibodies. 55.5% of the instances of Cryptosporidium sp infestation were found in children less than 4 years old. The higher incidence was in winter and spring. The association with other enteropathogens was found in 14.8%. Diarrhea and abdominal pain were the most common clinical features of cryptosporidial disease. Chronic diarrhea was found in two adult patients with acquired immunodeficiency syndrome. In immunocompromised children and adults asymptomatic carriers were found. The sensitivity and specificity of immunofluorescence testing with monoclonal antibodies as compared with Ziehl-Neelsen stain for the detection of Cryptosporidium sp oocysts were 100%.

Inability of oral bovine transfer factor to eradicate cryptosporidial infection in a patient with congenital dysgammaglobulinemia

A 31-year-old man with dysgammaglobulinemia Type I (deficient IgG, IgA, and elevated IgM) and persistent cryptosporidiosis was treated over a 13-week period with oral bovine transfer factor from calves immunized with cryptosporidia. Spiramycin was added toward the end of the treatment period. This patient failed to show clinical response although there was a decrease in the stool oocyst count from the value just prior to therapy. Bovine transfer factor alone and in combination with spiramycin failed to eradicate the infection in this man with well-documented stable cryptosporidiosis.