Outbreak of cryptosporidiosis associated with a water sprinkler fountain--Minnesota, 1997

Cryptosporidiosis associated with recreational water exposure is becoming recognized more frequently. This report summarizes the investigation of a large outbreak of cryptosporidiosis associated with exposure to a water sprinkler fountain at the Minnesota Zoo. The initial cases were not diagnosed as cryptosporidiosis by the health-care system despite patients seeking care, underscoring the need for increased awareness of cryptosporidiosis and routine laboratory diagnostic practices among health-care providers.

Discrepancy between sex- and water-associated risk behaviors for cryptosporidiosis among HIV-infected patients in San Francisco

OBJECTIVE

Potential transmission of cryptosporidiosis through drinking water supplies has been highly publicized; however, it is unknown whether this reporting has increased patient awareness or reduced other risk behaviors for exposure to this organism, such as high-risk sexual behavior.

METHODS

Consecutive patients presenting for initial evaluation to the Gastroenterology AIDS Clinic completed a questionnaire that assessed knowledge about cryptosporidiosis, perceived risk of infectious diarrhea, drinking water sources, and high-risk sexual behavior.

RESULTS

Fifty-one patients completed the questionnaire (82% male; 86% homosexual; mean age, 38 years; median CD4 count, 136 x 10(6) cells/L). Most respondents (31 of 44; 70%) believed they were at risk for infectious diarrhea. Awareness of cryptosporidiosis was high (31 of 45; 69%) as was avoidance of tap water (26 of 51; 51%) and exclusive or frequent use of bottled or boiled water (40 of 51; 78%). Respondents who used bottled water reported spending an average of $331.76 U.S. annually. However, high-risk sexual behavior remained common: 21 (41%) of the 51 subjects reported unprotected anal intercourse or oral-anal sexual contact. High-risk sexual behavior was prevalent even among subjects who drank exclusively boiled or bottled water.

CONCLUSIONS

Awareness of risk for infectious diarrhea and cryptosporidiosis is high among patients infected with HIV in San Francisco. Patients perceive drinking water to be a substantial risk factor for infectious diarrhea and incur significant expense to avoid tap water. However, high-risk sexual behaviors remain prevalent in this population and should be the focus of future education efforts.

[Pulmonary crytosporidium in a patient with AIDS]

Compared to digestive disorders, respiratory disease linked to cryptosporidium has not been very well documented in AIDS. We report a case of a patient suffering from AIDS who presented with chronic bronchial symptoms which became more and more incapacitating. Different respiratory specimens (broncho-alveolar lavage, expectoration and bronchial biopsy) revealed the presence of cryptosporidium species. The patient died in a few weeks from respiratory insufficiency without the parasite being eradicated from the bronchi. Although the autopsy confirmed the presence of cryptosporidium species, it was difficult to confirm its responsibility due to the fact that other pathogens were present in the bronchial tree.

Cryptosporidium parvum infection in experimentally infected mice: infection dynamics and effect of immunosuppression

The effect of mouse strain, age, sex, and the size of infective dose on the susceptibility to infection with the coccidium Cryptosporidium parvum Tyzzer, 1912 was determined using several murine models. Mice were infected with C. parvum oocysts originally of cervine origin, maintained by repeat passage in calves. All mice in the experimental groups proved susceptible to infection, though this resulted asymptomatic in all cases. C. parvum infection in BALB/c and Porton mice exhibited some variation. BALB/c mice demonstrated a longer prepatent period than Porton mice. They also produced a greater oocyst output over the patent period, though the differences were not statistically significant. Differences were observed between mice infected at either 3 or 4 weeks of age. Prepatent period was shorter in those mice infected at 3 weeks of age, reaching 100% infection rate by day 7 post-inoculation. The patent period was longer in younger mice showing that age at time of infection can modify the oocyst shedding profile. However, no sex related differences in the course of infection were observed. The effect of different infective doses of oocysts was analysed. The three doses used (10(4), 10(5), 10(6)) proved infective for all mice, there were no statistical differences in either prepatent or patent periods, or in the oocyst shedding profiles. Experimental cryptosporidiosis was also induced in cyclophosphamide-immunosuppressed mice. Cyclophosphamide was orally administered by stomach tube at a dose of 50 mg/kg/day starting 10 days before the intragastric inoculation of 10(6) oocysts of C. parvum per mouse and continuing until the end of the experiment. Immunosuppressed mice had a shorter prepatent period, remained infected longer and shed more oocysts than immunocompetent mice. Immunosuppression produced high mortality rates; during the course of the experiment 44% of immunosuppressed-infected and 30% of immunosuppressed-uninfected mice died. There were no deaths in the untreated groups. Differences in the clinical course of the infection were also observed between immunosuppressed and immunocompetent mice; however, some mice recovered without immunosuppression withdrawal.

Foodborne outbreak of cryptosporidiosis--Spokane, Washington, 1997

On December 29, 1997, the Spokane Regional Health District received reports of acute gastroenteritis among members of a group attending a dinner banquet catered by a Spokane restaurant on December 18. The illness was characterized by a prolonged (3-9 days) incubation period and diarrhea, which led public health officials to suspect a parasitic cause of the illness. Eight of 10 stool specimens obtained from ill banquet attendees were positive for Cryptosporidium using both modified acid-fast and auramine-rhodamine staining of concentrated specimens. This report summarizes the epidemiologic investigation of the outbreak, which suggests that foodborne transmission occurred through a contaminated ingredient in multiple menu items.

Natural history and biology of Cryptosporidium parvum

The taxonomy of the genus Cryptosporidium remains ambiguous, because the current criteria for speciation are insufficient to validate the 6-8 named species. Cross-transmission experiments have shown varying and conflicting results, and the limited genetic data available do not necessarily support currently proposed species designations. The reasons for this ambiguity lie with the ubiquitous nature of Cryptosporidium, probably infecting all vertebrates and variety of tissues therein, and the absence of reference strains with defined virulence attributes that can be linked to genetic markers for comparative analysis. The inability to classify oocysts or confidently to identify their origin, implicate oocysts from all sources as hazardous to humans. Another major issue is the unusual degree of resistance that Cryptosporidium has shown to antiprotozoan and antimicrobial agents. The intracellular but extracytoplasmic domain the parasite occupies is in itself a significant barrier to drug entry. In support of this we outline how the intracellular niche of this parasite differs from the related Apicomplexans, Plasmodium and Toxoplasma, and delineate why the feeder organelle membrane, rather than, or in addition to, the parasitophorous membrane, is the major portal of nutrient entry for Cryptosporidium. The broad conclusion is that anticryptosporidial agents will have to enter the parasite via the multiple apical membranes that camouflage the parasite, or via the host cell, possibly transported by vesicles to the feeder organelle membrane. This may have major implications for rational drug discovery and design.

Water-borne cryptosporidiosis: detection methods and treatment options

Since the infamous outbreak in Milwaukee, WI, USA, of water-borne cryptosporidiosis affecting over 400,000 people, there have been at least 20 smaller outbreaks associated with this parasite in the UK and North America. These events have led to an explosion of interest in and research on the nature of cryptosporidiosis as a dangerous water-borne pathogen, particularly patients with acquired immune deficiency syndrome (AIDS). In addition, several major environmental laws and proposed regulations specifically address the control of this parasite. The possible ramifications of these laws include billions of dollars of modifications to water-treatment facilities in the USA. Unfortunately, the methods used to gather the information on which these laws are based have serious deficiencies that could lead to gross underestimation of the magnitude of this problem. The present review considers gaps in our understanding of water-borne cryptosporidiosis, new methods under investigation that could improve our ability to monitor water for the presence of this organism, and treatment and control strategies to limit the threat to our water supplies.

Other food borne infections

This article presents an update of several emerging or reemerging pathogens: Yersinia, Cryptosporidia, Cyclospora, Brucella, and Mycobacterium. All of these zoonotic pathogens show evidence of food borne transmission. Yersiniosis is presented as an emerging pathogen that has as its major route of transmission preparation and consumption of pork products. New evidence is presented that supports the transmission of brucellosis via the food chain, especially through contaminated raw milk and cheese. While TB has limited transmission via raw milk, it is highlighted as a reemerging infection due to the development of multiple drug resistance. Public health veterinarians stand in an excellent position to recognize these emerging diseases and apply intervention strategies to prevent and control these infections in the future. This article is intended to raise their consciousness as to the management and medical practices that can diminish food borne transmission.

Treatment of HIV-1-associated microsporidiosis and cryptosporidiosis with combination antiretroviral therapy

BACKGROUND

Enterocytozoon bieneusi and Cryptosporidium parvum cause chronic antimicrobial-resistant gastrointestinal infections in HIV-1-infected individuals. HIV-1 reverse transcriptase inhibitors delay the onset of opportunistic infections, but are not known to reverse established infections. HIV-1 protease inhibitors are more effective across a broader range of HIV-1-infected immune cells. Combination antiretroviral therapy that includes a protease inhibitor could improve immunity to E bieneusi and C parvum.

METHODS

HIV-1 infected patients with chronic microsporidiosis (five), cryptosporidiosis (three), or dual infection (one), were treated with combination therapy that included at least one HIV-1 protease inhibitor. Outcome measures were symptoms, weight, use of antidiarrhoeal and antimicrobial drugs, T-lymphocyte subsets, HIV-1 viraemia, stool microscopy, and biopsy by endoscopy.

FINDINGS

All patients had complete clinical responses, gained a median 15 kg in weight, and ceased all antidiarrhoeal and antimicrobial therapies. Biliary cryptosporidiosis responded in both affected patients. Neither pathogen was detected in follow-up stool microscopy (eight of eight patients) or in biopsy samples by endoscopy (five of five). Intestinal architecture returned to normal in three patients. There was a dense CD8 lymphocyte and macrophage infiltrate and staining of intraepithelial E bieneusi with interferon-gamma before and after treatment, but little staining for CD4 or B lymphocytes, interleukin 10, or HIV-1 gp41. Five patients remained symptom-free after a median 13 months follow-up. Four patients had recurrent diarrhoea at 7-13 months (one with positive stool microscopy), associated with declining CD4 counts.

INTERPRETATION

Combination antiretroviral therapy that includes a protease inhibitor can restore immunity to E bieneusi or C parvum in HIV-1 infected individuals, and result in complete clinical, microbiological, and histological responses. The persistent CD8 cell and macrophage infiltrate, and the rapid time to relapse in patients with declining CD4 lymphocyte counts, suggest that neither infection was eradicated.

Cryptosporidiosis-associated mortality following a massive waterborne outbreak in Milwaukee, Wisconsin

OBJECTIVES

This study estimated the magnitude of cryptosporidiosis-associated mortality in the Milwaukee vicinity for 2 years following a massive waterborne outbreak.

METHODS

Death certificates were reviewed.

RESULTS

During approximately 2 years before the outbreak, cryptosporidiosis was listed as an underlying or contributing cause of death on the death certificates of four Milwaukee-vicinity residents. In the approximately 2 years after the outbreak, this number was 54, of whom 85% had acquired immunodeficiency syndrome (AIDS) listed as the underlying cause of death. In the first 6 months after the outbreak, the number of death certificates indicating AIDS, but not cryptosporidiosis, as a cause of death was 19 (95% confidence interval = 12.26) higher than preoutbreak trends would have predicted.

CONCLUSIONS

Waterborne outbreaks of cryptosporidium infection can result in significant mortality, particularly among immunocompromised populations. Any discussion of policies to ensure safe drinking water must consider the potential fatal consequences of waterborne cryptosporidiosis among immunocompromised populations.

Outbreak of cryptosporidiosis associated with a swimming pool in Andover

An outbreak of eight cases of cryptosporidiosis in Hampshire over a period of eight weeks in the summer of 1996 was linked to use of one swimming pool. Cryptosporidial oocysts were not isolated from samples of backwash, but the presence of enterobius ova indicated faecal contamination and a case control study including the first four primary cases suggested an association with immersion in the pool. Even in small outbreaks case control studies can provide useful supportive evidence as to the possible source of infection.

Cryptosporidiosis after CD34-selected autologous peripheral blood stem cell transplantation (PBSCT). Treatment with paromomycin, azithromycin and recombinant human interleukin-2

We report two cases of cryptosporidiosis after CD34-selected PBSCT for lymphoma. While the first patient died of pulmonary cryptosporidiosis, treatment with paromomycin, azithromycin and subcutaneous low-dose rhIL-2 to improve numerical and functional T lymphocyte defects completely eliminated infection in the second patient. We conclude, that the removal of mature T lymphocytes by positive selection of CD34+ cells bears the risk of a delayed immune reconstitution resulting in an increased incidence of severe and sometimes fatal opportunistic infections. IL-2 might be useful in this situation by accelerating immune reconstitution and reducing the danger of opportunistic infections.

Outbreaks of Escherichia coli O157:H7 infection and cryptosporidiosis associated with drinking unpasteurized apple cider--Connecticut and New York, October 1996

In October 1996, unpasteurized apple cider or juice was associated with three outbreaks of gastrointestinal illness. In the Western United States, an outbreak of Escherichia coli O157:H7 infections associated with unpasteurized commercial apple juice caused illness in 66 persons and one death. In addition, one outbreak of apple cider-related E. coli O157:H7 infections and another of cider-related Cryptosporidium parvum infections occurred in the Northeast. Apple cider is a traditional beverage produced and consumed in the fall. Cider often is manufactured locally at small cider mills where apples are crushed in presses, and the cider frequently is not pasteurized before sale. This report summarizes the clinical and epidemiologic features of the two apple cider-related outbreaks, which suggest that current practices for producing apple cider may not be adequate to prevent microbial contamination.

Cryptosporidium infection in infancy as a cause of malnutrition: a community study from Guinea-Bissau, west Africa

Cryptosporidium parvum causes persistent diarrhea in young children in developing countries. To determine the interaction between nutritional status and cryptosporidiosis, an open cohort of 1064 children younger than 3 y of age was followed for 1441 child-years by weekly diarrhea recall visits. A total of 5072 weight and 4264 height measurements was made. There were no tendencies of low weight (P = 0.38) or height (P = 0.16) in children who acquired cryptosporidiosis. Cryptosporidiosis in infancy was accompanied by an estimated weight loss of 392 g (95% CI: 247, 538 g) in boys and 294 g (95% CI: 109, 479 g) in girls, corresponding to 3.7% and 2.9% of mean weight, respectively, at 2 y of age. No significant catch-up growth covered for this loss in weight. A similar effect in linear growth was shown (P = 0.02). Although it has been suggested that the effect of infections on nutrition is usually transient because of catch-up growth, the present study suggests that cryptosporidiosis in infancy has a permanent effect on growth.

Cryptosporidiosis and blastocystosis in renal transplant recipients

Some intestinal parasitic infections are frequently seen in renal transplant recipients. Parasites such as Cryptosporidium spp. and Blastocystis hominis are often asymptomatic or responsible for limited infections in normals, but may cause prolonged and heavy infections with gastrointestinal complaints, mainly diarrhea, in immunocompromised patients. Such infections can often not be detected by routine diagnostic procedures, but special concentration and staining methods are needed. We investigated 115 fecal specimens from 69 renal transplant recipients and 42 fecal specimens from 42 control cases. Of the 69 recipients, 27 (39.1%) had B. hominis and 13 (18.8%) had Cryptosporidium spp. in at least one fecal specimen. Prevalence of symptomatic Cryptosporidium infections was significantly higher in the renal transplant recipients, when compared with the control group (p < 0.05). Special parasitological procedures must be performed in immunocompromised patients with chronic gastrointestinal complaints. Disappearance of symptoms after antiparastic drugs in some of 16 symptomatic patients are described, suggesting that these infections are more pathogenic in transplant recipients.

Cryptosporidiosis: an emerging, highly infectious threat

Cryptosporidium parvum, a leading cause of persistent diarrhea in developing countries, is a major threat to the U.S. water supply. Able to infect with as few as 30 microscopic oocysts, Cryptosporidium is found in untreated surface water, as well as in swimming and wade pools, day-care centers, and hospitals. The organism can cause illnesses lasting longer than 1 to 2 weeks in previously healthy persons or indefinitely in immunocompromised patients; furthermore, in young children in developing countries, cryptosporidiosis predisposes to substantially increased diarrheal illnesses. Recent increased awareness of the threat of cryptosporidiosis should improve detection in patients with diarrhea. New methods such as those using polymerase chain reaction may help with detection of Cryptosporidium in water supplies or in asymptomatic carriers. Although treatment is very limited, new approaches that may reduce secretion or enhance repair of the damaged intestinal mucosa are under study.

Treatment of severe diarrhea caused by Cryptosporidium parvum with oral bovine immunoglobulin concentrate in patients with AIDS

We prospectively evaluated the safety and efficacy of colostrum-derived bovine immunoglobulin concentrate in the treatment of diarrhea caused by Cryptosporidium parvum in patients with AIDS. A total of 24 patients with severe chronic diarrhea and AIDS were stratified to one of three cohorts: (1) C. parvum infection alone (n = 16), (2) C. parvum and a second opportunistic infection (n = 4), and (3) idiopathic AIDS enteropathy with no identified source of infection (n = 3) or an untreatable opportunistic infection other than C. parvum (n = 1). All patients were treated with bovine immunoglobulin concentrate for 21 consecutive days. Patients in cohort 1 were randomized to receive the medication in powder or capsule forms, whereas all patients in cohorts 2 and 3 received the powder form. The primary end point was change in mean daily stool weight. Secondary end points included change in stool frequency and body weight, as well as clearance of C. parvum oocytes as analyzed on stool microscopy. Patients with C. parvum who were treated with bovine immunoglobulin concentrate in powder form experienced a significant decrease in mean stool weight, from 1,158 +/- 114 g/day at baseline, to 595 +/- 63 g/day (p = 0.04) at the end of treatment, and 749 +/- 123 g/day (p = 0.03) 1 month after completing treatment. Stool frequency decreased from 6.6 +/- 0.6 bowel movements per day at study entry, to 5.4 +/- 0.7 during treatment (p = 0.04), and 5.4 +/- 0.9 during observation (p = 0.12). Patients who received bovine immunoglobulin concentrate in capsule form and patients without C. parvum (cohort 3) showed no improvement. No serious side effects were observed, and the medication was well tolerated. Thus, bovine colostrum immunoglobulin concentrate, in powder form, appears promising in the treatment of severe diarrhea caused by C. parvum. The optimal dosage, duration of therapy, and overall efficacy need to be determined in placebo-controlled trials.

Factors associated with microsporidial and cryptosporidial diarrhea in HIV infected patients

Cryptosporidium and microsporidia are increasingly recognized as important agents of chronic diarrhea in human immunodeficiency virus (HIV) infected patients. These protozoa present clinical and biological similarities but coinfection with these two parasites seems uncommon in a population of diarrheic HIV infected patients in the Paris area (France), a comparison study was performed in order to clarify epidemiological differences between these protozoa. From November 1993 to December 1994, 26 microsporidial infected patients were compared to 28 cryptosporidial patients for various factors. Results of a multivariate logistic regression analysis showed that trips to tropical countries remained strongly associated with microsporidic compared with Cryptosporidium adjusted odds ratio [OR] = 4.6, 95% confidence interval [CI] 1.1-19.5). Thus, as compared with cryptosporidiosis, specific epidemiological factors could be associated with microsporidial transmission in tropical countries.

Cryptosporidiosis among patients infected with human immunodeficiency virus. Factors related to symptomatic infection and survival

The authors reviewed the medical records of 194 human immunodeficiency virus (HIV)-positive patients newly diagnosed with cryptosporidiosis and all 3,564 patients with newly diagnosed acquired immunodeficiency syndrome (AIDS) at San Francisco General Hospital for the period 1986-1992. The study was designed to address three questions: 1) How do AIDS patients who present with cryptosporidiosis differ from other patients with AIDS? 2) What factors are associated with survival among AIDS patients with newly diagnosed cryptosporidiosis? 3) Does a diagnosis of cryptosporidiosis impact survival after AIDS diagnosis? A total of 194 cases of cryptosporidiosis among HIV-infected patients were identified during the study period. Of the 194 patients, 109 (56%) had no prior diagnosis of AIDS. These 109 patients represented 3.1% of the 3,564 newly diagnosed cases of AIDS in the same period. Among the 134 patients with CD4 T-lymphocyte counts performed within 3 months of Cryptosporidium diagnosis, 34 (25%) had CD4 counts greater than 209 cells/ml. In a multivariate conditional logistic regression model, the incidence of Cryptosporidium was related to ethnicity (for blacks vs. whites, matched odds ratio (OR) = 0.15, 95% confidence interval (CI) 0.03-0.73), CD4 count (for a CD4 count of < or = 53 cells/ml vs. > 53 cells/ml, matched OR = 12.60, 95% CI 4.01-39.61), and age (for a 10-year increase, matched OR = 0.51, 95% CI 0.27-0.98). Two factors measured at the time of Cryptosporidium diagnosis were identified as being independently associated with survival (p < 0.001) in the proportional hazards model: CD4 count < or = 53 cells/ml versus > 53 cells/ml (relative hazard = 6.18, 95% CI 2.99-12.76) and hematocrit < or 37% versus > 37% (relative hazard = 2.27, 95% CI 1.22-4.22). The median durations of survival in the four subgroups of Cryptosporidium-infected patients defined by these two variables differed significantly from each other (range, 204-1,119 days). Cryptosporidiosis as an initial AIDS-defining diagnosis was associated with an elevated relative hazard of death in comparison with other AIDS-defining diagnoses (relative hazard = 2.01, 95% CI 1.38-2.93). These data identify the groups of HIV-infected individuals at risk for presentation with symptomatic Cryptosporidium infection; the distinct survival patterns among subgroups of those patients already infected with this parasite; and the survival of AIDS patients with newly diagnosed cryptosporidiosis relative to patients with other AIDS-defining conditions. Such information is necessary for the design of prospective studies, the development of prophylactic strategies, the evaluation of candidate therapies, and the provision of prognostic information to patients.

Cryptosporidiosis in Wisconsin: a case-control study of post-outbreak transmission

During March-April 1993, an estimated 403000 residents of the 5-county greater Milwaukee, Wisconsin area developed cryptosporidiosis after drinking contaminated municipal water. Although the number of cases dropped precipitously after the implicated water plant closed on 9 April, cases continued to occur. To investigate risk factors for post-outbreak cryptosporidiosis, 33 Milwaukee-area residents who had laboratory-confirmed Cryptosporidium infection with onset of diarrhoea between 1 May and 27 June 1993 were interviewed by telephone. Of these, 28 (85%) had onset of diarrhoea during May, 12 (36%) had watery diarrhoea during the outbreak, and 5(15%) were HIV-infected. In a neighbourhood-matched case-control study, immunosuppression (matched odds ratio (MOR) not calculable, 95% confidence interval (CI) 3.0, infinity) and having a child less than 5 years old in the household (MOR = 17.0, CI 2.0, 395.0) were independently associated with infection. When persons who had diarrhoea during the outbreak were excluded, immunosuppression remained significantly associated with illness (MOR not calculable, CI 1.6, infinity). Cryptosporidium transmission continued after this massive waterborne outbreak but decreased rapidly within 2 months.

Cryptosporidiosis in children who visited an open farm

In the summer of 1995, cryptosporidiosis was diagnosed in a child in hospital. This child had taken part in a summer activity project involving 161 children and nine adults. Reports of a similar illness among a number of other participants prompted an outbreak investigation. A cohort study was conducted in two phases. Thirteen children (aged 6 to 15 years) out of 161 respondents to the first questionnaire met the case definition for illness and cryptosporidium was detected in stools from seven of the 13. Illness was significantly associated with child participants who had visited an open farm (p < .000005). Nine of the cases sought medical attention, and two were admitted to hospital. The second phase of the cohort study was conducted among 52 of the 55 people who had visited the open farm. Illness was significantly associated with playing in sand to which animals had access, at the edge of a stream beside a picnic area (p < .005). Contact with various animals was not associated with illness. This outbreak emphasises the risk for children of visiting open farms. Managers of open farms need to be aware of the potential for transmission of infectious diseases to visiting children. Strict implementation of hygiene measures is essential to minimise risk.

Cryptosporidium related diarrhoea

Cryptosporidium is an apicomplexan parasite which causes self limited diarrhoea in immuno-competent persons and severe life threatening disease in immuno-compromised individuals, particularly, to patients suffering from acquired immunodeficiency syndrome (AIDS). Because of increased incidence of HIV (human immunodeficiency virus), the protozoan parasite has found the human host to be ideal for perpetuation and propagation, resulting in a natural amplification of this parasite. Much less is known about Cryptosporidium in India, although, it is clear that this parasite is going to be a major enteric pathogen in coming years, considering the increasing number of HIV cases that are being reported in this country. This presentation reviews the current advances in our knowledge about the clinical significance, epidemiology and treatment of cryptosporidiosis.

Severe, protracted intestinal cryptosporidiosis associated with interferon gamma deficiency: pediatric case report

We describe a human immunodeficiency virus-negative infant with chronic intractable diarrhea due to Cryptosporidium parvum; he had a history of significant weight loss since the second week of life. A preliminary study of his immune function was negative for primary immunodeficiency. To further study his immune function, proliferation of peripheral blood mononuclear cells (PBMCs) was elicited by crude antigenic extract from C. parvum oocysts (CCE). Supernatants of CCE-stimulated PBMCs contained interleukin 10 but not interferon gamma (IFN-gamma), while PBMCs from a control (a 2-year-old immunocompetent infant who had recovered from cryptosporidiosis) showed a strong response to IFN-gamma when stimulated with CCE. These results stress the role of IFN-gamma in recovery from cryptosporidiosis.

Opportunistic intestinal protozoa in chronic diarrhoeic immunosuppressed patients

Chronic diarrhoea accompanied by weight loss is a common and often debilitating problem in immunocompromized patients, receiving chemotherapeutic agents. In these patients, the intestinal opportunistic parasites probably played a major role in causing this clinical manifestation. The present work, aims to search for these parasites. Special stains for each parasite were used to differentiate it easily from the fecal elements, obviating the need for diagnostic invasive techniques especially used in microsporidial infection. The detected parasites were, Giardia lamblia (17.7%) best seen by iron haematoxylin stain. Coccidian oocysts (Cryptosporidia; 13.3% Isospora belli; 2.2%) were clearly seen by using Ziehl-Neelsen and Chromotrope-based stains. The Gram positive spores of Enterocytozoon bieneusi were (4.4%) and best seen by using chromotrope-based stain, where as Giemsa failed in their diagnosis.

Biliary cryptosporidiosis in HIV-infected people after the waterborne outbreak of cryptosporidiosis in Milwaukee

BACKGROUND

In March 1993, the municipal water supply in Milwaukee became contaminated with cryptosporidium and a widespread outbreak of cryptosporidiosis occurred.

METHODS

We retrospectively studied the relations among the clinical presentation, CD4 count, and survival in a group of 82 patients infected with the human immunodeficiency virus (HIV) in whom cryptosporidiosis developed during the outbreak. Infection was documented by the finding of cryptosporidium in stool.

RESULTS

There was a sharp increase in the number of HIV-infected patients with cryptosporidiosis after the period of water contamination. Four of 24 patients with biliary symptoms (17 percent) and 30 of 58 without biliary symptoms (52 percent) were alive one year after the outbreak (P = 0.003). Twenty-one of the patients with biliary symptoms had CD4 counts < or = 50 per cubic millimeter, as compared with 36 of 57 patients without biliary symptoms (88 percent vs. 63 percent, P = 0.03). The CD4 count was not available for one patient in the latter group. Within one year, 41 of the patients with CD4 counts < or = 50 per cubic millimeter had died, as compared with 6 of those with higher counts (72 percent vs. 25 percent, P < 0.001). After adjustment for the CD4 count, independent predictors of death were older age and the presence of nausea and vomiting.

CONCLUSIONS

When HIV-infected patients are exposed to cryptosporidium, those with CD4 counts < or = 50 per cubic millimeter are at increased risk for biliary symptoms and for death within one year after the infection.

Biliary tract cryptosporidiosis immunosuppressed rat model

Rats immunosuppressed by hydrocortisone acetate and a low protein diet were challenged with Cryptosporidium Parvum oocysts and studied on days 10, 35 and 70 post-infection. The biliary tract was found to be a major site of parasite infection. C. parvum was visible in the biliary papillary area in association with a proliferation of highly convoluted tubular glands. The papillary lumen was narrowed, and an upstream dilation with bacterial proliferation was seen. The liver was initially free of lesions, and subsequently exhibited late lesions of cholestasis. Parasites were not found in the pancreatic duct, although pancreatitis was frequently observed. Oocysts were consistently present in the distal portion of the ileum. Both challenged and unchallenged immunosuppressed rats, exhibited widespread focal hepatic infarcts and pyelonephritis. Other organs appeared free of lesions. In addition to the intestine, data identified the biliary tract as a major site of C. parvum infection and as a potential protected reservoir which may sustain a chronic infection.

Asymptomatic carriage of intestinal Cryptosporidium in immunocompetent and immunodeficient children: a prospective study

Little information is available on asymptomatic carriage of Cryptosporidium in immunocompetent and immunodeficient children. We prospectively studied a group of asymptomatic children, 78 immunocompetent and 50 immunodeficient, to document the incidence of asymptomatic carriage of cryptosporidiosis in such a population. We also investigated whether the treatment of children who carried asymptomatic cryptosporidiosis could help in reducing their risk of gastrointestinal symptoms as well as the shedding of infectious oocysts. The occurrence of multiple infections with common intestinal pathogens including Giardia lamblia was also investigated. Asymptomatic cryptosporidiosis was documented in 6.4% of immunocompetent and 22% of immunodeficient children. In a control symptomatic population Cryptosporidium was found in 4.4% of immunocompetent and 4.8% of immunodeficient children. Asymptomatic carriage of Cryptosporidium was documented in 2 human immunodeficiency virus-infected children, one of whom also carried Giardia asymptomatically. Treatment with spiramycin (100 mg/kg daily for 14 days) reduced significantly the duration of the shedding of potentially infectious oocysts. Finally no gastrointestinal symptoms developed in children treated for asymptomatic infection with Cryptosporidium, whereas children who were not treated developed gastrointestinal symptoms.

An outbreak of cryptosporidiosis in south London: what value the p value?

An outbreak of cryptosporidiosis which affected 44 people in January and February 1991 was identified through local surveillance at a South London Public Health Laboratory. Preliminary enquiries revealed that more than half the patients were adult and that there were no common factors other than geographical association. A case-control study showed a significant association between illness and consumption of tap water supplied by a particular water company, as well as a dose response effect. There were no apparent breaches or irregularities in the water distribution system and no indication of a problem through routine monitoring indices. This incident demonstrates the problems of establishing the source of cryptosporidiosis outbreaks in the absence of evidence of environmental abnormality, as well as possibly indicating that water conforming to current treatment standards may occasionally contain sufficient numbers of Cryptosporidium oocysts to cause sporadic cases or clusters.

An outbreak of waterborne cryptosporidiosis associated with a public water supply in the UK

In November and December 1992, an outbreak of waterborne cryptosporidiosis occurred in Bradford, a city in the North of England. In all 125 cases were involved, the majority of whom lived in part of the city which received its drinking water supply from a single water treatment works. A case control study demonstrated an association between illness and the consumption of tapwater from this source; those drinking large volumes being more likely to have been ill. Treated water from the defined source yielded cryptosporidial oocysts. Heavy rainfall was recorded in the catchment area of the reservoir supplying raw water to the treatment works, immediately prior to the probable time of infection, based on dates of onset of illness.

Assessing the public health threat associated with waterborne cryptosporidiosis: report of a workshop

In September 1994, CDC convened a meeting to address the public health threat associated with waterborne cryptosporidiosis. Representatives from 40 states and from regulatory and public health agencies, water utility companies, and advocacy groups discussed approaches to avoiding unnecessary boil-water advisories (i.e., statements to the public advising persons to boil water before drinking it) and preventing and controlling waterborne cryptosporidiosis. Work groups at the meeting addressed four issues: 1) surveillance systems and epidemiologic study designs; 2) public health responses when oocysts are detected in drinking water; 3) cryptosporidiosis in immunocompromised persons; and 4) water sampling methods and interpretation of results. The work groups defined the problems associated with these issues and developed strategies that could be used initially to manage these problems. The work group discussions were summarized, and the conclusions were provided as either a) summaries of current knowledge concerning that issue or b) suggested ways to obtain the information needed to develop useful recommendations. The work group conclusions are for consideration by persons and organizations who must assist with these issues and by those who seek to advance understanding of waterborne cryptosporidiosis.

[Chronic diarrhea and Cryptosporidium in diabetic patients with normal lymphocyte subpopulation. 2 case reports]

Two cases of diabetic patients with normal TCD4+ cell count with chronic diarrhoea and Cryptosporidium are described herein. In both cases serologic tests for HIV were negative. The fact that these patients developed a pathology usually seen in presence of low TCD4+ cell counts suggests that some immune defect other than cellular might be involved in the pathogenesis of this infection. Authors concluded that intentional search for Cryptosporidium should be considered in the study of the diabetic patient with chronic diarrhoea.

Effect of sodium hypochlorite exposure on infectivity of Cryptosporidium parvum oocysts for neonatal BALB/c mice

Oocysts of Cryptosporidium parvum suspended in 5.25, 2.63, or 1.31% aqueous sodium hypochlorite (Clorox laundry bleach) for 10, 30, 60, or 120 min at 21 degrees C were administered by gastric intubation to neonatal BALB/c mice. Microscopic examination of intestinal tissue sections revealed developmental stages of C. parvum in all of the mice.

Case report: inhalation therapy of paromomycin is effective for respiratory infection and hypoxia by cryptosporidium with AIDS

A 24-year-old man with AIDS and hemophilia A had intractable diarrhea and fever. Upon examination of stool and of a sigmoidal biopsy specimen, cryptosporidium was revealed. Approximately 2 months after admission, respiratory infection with hypoxia due to cryptosporidium developed. Paromomycin inhalation was effective therapy. To the authors' knowledge, this is the first case of respiratory cryptosporidiosis treated successfully by paromomycin inhalation.

Municipal drinking water and cryptosporidiosis among persons with AIDS in Los Angeles County

To assess unfiltered drinking water as a source of cryptosporidium infection in patients with the acquired immunodeficiency syndrome (AIDS) the prevalence of cryptosporidiosis among persons with AIDS in Los Angeles County was assessed by water service area. One water distributor, serving approximately 60% of the county's residents (area B), has consistently employed filtration. The other company, which serves the remainder of the county (area A), did not institute filtration until mid-December 1986. This difference provided a 'natural experiment' in which to assess the effect of municipal water filtration on the level of cryptosporidiosis among persons with AIDS. The prevalence of cryptosporidiosis among AIDS patients was compared for the two water service areas for the time period (1983-6) preceding the implementation of filtration in area A. From 1983 to 1986 the age-standardized prevalence of cryptosporidiosis among AIDS patients was 32% lower in area A (4.2%), which received unfiltered water, than in area B (6.2%). Following addition of filtration in area A, the prevalence of cryptosporidiosis among AIDS patients decreased by 20%; however, a decline, of 47%, was also observed in area B. The similar baseline levels of cryptosporidiosis and the corresponding post-filtration decline in both areas suggest that filtration had no effect on levels of cryptosporidiosis among persons with AIDS. Thus it does not appear that municipal drinking water is an important risk factor for cryptosporidiosis in AIDS patients residing in Los Angeles County.