Seasonal profile and level of CD4+ lymphocytes in the occurrence of cryptosporidiosis and cystoisosporidiosis in HIV/AIDS patients in the Triângulo Mineiro region, Brazil

Past, current, and potential treatments for cryptosporidiosis in humans and farm animals: A comprehensive review

The intracellular protozoan parasite of the genus Cryptosporidium is among the leading causes of waterborne diarrheal disease outbreaks throughout the world. The parasite is transmitted by ingestion of infective oocysts that are highly stable in the environment and resistant to almost all conventional disinfection methods and water treatments. Control of the parasite infection is exceedingly difficult due to the excretion of large numbers of oocysts in the feces of infected individuals that contaminate the environment and serve as a source of infection for susceptible hosts including humans and animals. Drug development against the parasite is challenging owing to its limited genetic tractability, absence of conventional drug targets, unique intracellular location within the host, and the paucity of robust cell culture platforms for continuous parasite propagation. Despite the high prevalence of the parasite, the only US Food and Drug Administration (FDA)-approved treatment of Cryptosporidium infections is nitazoxanide, which has shown moderate efficacy in immunocompetent patients. More importantly, no effective therapeutic drugs are available for treating severe, potentially life-threatening cryptosporidiosis in immunodeficient patients, young children, and neonatal livestock. Thus, safe, inexpensive, and efficacious drugs are urgently required to reduce the ever-increasing global cryptosporidiosis burden especially in low-resource countries. Several compounds have been tested for both in vitro and in vivo efficacy against the disease. However, to date, only a few experimental compounds have been subjected to clinical trials in natural hosts, and among those none have proven efficacious. This review provides an overview of the past and present anti-Cryptosporidium pharmacotherapy in humans and agricultural animals. Herein, we also highlight the progress made in the field over the last few years and discuss the different strategies employed for discovery and development of effective prospective treatments for cryptosporidiosis.

The implementation of the Kinyoun staining technique in a resource-limited setting is feasible and reveals a high prevalence of intestinal cryptosporidiosis in HIV patients

OBJECTIVES

In resource-limited settings, intestinal Cryptosporidia or coccidian infections are common causes of chronic diarrhoea, but usually remain undiagnosed by routine stool investigation. Here, the addition of the Kinyoun staining technique after stool concentration was evaluated as an easy and inexpensive method for diagnosis of intestinal parasitic infection in HIV-infected patients.

METHODS

This cross-sectional study investigated HIV-infected patients with diarrhoea and randomly selected HIV-infected patients without diarrhoea as controls. Stool samples were examined by wet mount microscopy and Kinyoun staining after stool concentration. Clinical, sociodemographic and behavioural data were collected. Statistical analysis was performed using Chi-squared test and multivariate regression analysis.

RESULTS

In total, 163 participants were included (62.0% female, mean age 38.2 [SD ±10.7] years). Diarrhoea was present in 52.1% (85/163). The prevalence of intestinal parasites was 18.4% (30/163). Cryptosporidia infections were more frequent among patients with diarrhoea (12.9% [11/85] vs. 1.3% [1/78], p=0.005) and in patients with CD4⁺ cell count <200 cells/µL (25.9% [7/27] vs. 3.7% [5/136], p=0.001). Risk factors for intestinal parasitic infections were diarrhoea and the habit of regularly eating uncooked food. Kinyoun staining was necessary for detection of cryptosporidiosis.

CONCLUSION

In our cohort, the prevalence of intestinal parasitic infection was high, especially after additional utilization of Kinyoun staining for detection of Cryptosporidia or intestinal coccidia. Considering its clinical relevance particularly in individuals at risk, the implementation of this technique should be considered in resource-limited settings.

Evaluation of Different Oocyst DNA Extraction Methods for Cryptosporidium spp. Research in Environmental Samples

PURPOSE

The major problem of the PCR method for the search of protozoan cysts/oocysts in environmental samples is the presence of inhibitors. DNA extraction methods capable of removing inhibitory substances of environmental origin and recovering the DNA are decisive for the efficiency of PCR. This study aimed to compare the efficiency of different DNA extraction methods for the search by Cryptosporidium oocysts in water samples by molecular methods.

METHODS

DNA extraction from water samples was performed using four different methods. Two methods use a chaotropic buffer to extract DNA and promote the selective binding of DNA to a silica membrane (GuSCN-silica and GFX Kit). The other method is based on the lysis and digestion of the samples in buffer and proteinase K, adsorption of impurities by an "InhibitEX" insertion matrix and purification of the DNA by a silica column (QIAamp Kit). The fourth method uses ionic and non-ionic detergents and proteinase K, to solubilize and separate the DNA from proteins, and a paramagnetic resin for DNA purification in the presence of high concentrations of guanidine ions (MAGNEX DNA Kit). Nested-PCR was performed, and the Cryptosporidium SSU rDNA gene amplified.

RESULTS

The results demonstrated that MAGNEX and GFX commercial kits showed higher sensitivity, with detection of up to 10⁰ oocysts/mL and 10⁴ oocysts/mL respectively.

CONCLUSION

In conclusion, this study confirmed that for low-DNA environmental samples, extraction methods should include an efficient oocyst wall breaking step, and showed that the best Cryptosporidium DNA extraction methods are those that use paramagnetic resins.

Cryptosporidiosis in HIV-positive patients and related risk factors: A systematic review and meta-analysis

Cryptosporidium is one of the major causes of diarrhea in HIV-positive patients. The aim of this study is to systematically review and meta-analyze the prevalence of Cryptosporidium in these patients. PubMed, Science Direct, Google Scholar, Web of Science, Cochrane and Ovid databases were searched for relevant studies dating from the period of 1 January 2000 to 31 December 2017. Data extraction for the included studies was performed independently by two authors. The overall pooled prevalence was calculated and subgroup analysis was performed on diagnostic methods, geographical distribution and study population. Meta-regression was performed on the year of publication, proportion of patients with diarrhea, and proportion of patients with CD4 < 200 cells/mL. One hundred and sixty-one studies and 51,123 HIV-positive participants were included. The overall pooled prevalence of Cryptosporidium infection in HIV-positive patients was 11.2% (CI95%: 9.4%–13.0%). The pooled prevalence was estimated to be 10.0% (CI95%: 8.4%–11.8%) using staining methods, 13.5% (CI95%: 8.9%–19.8%) using molecular methods, and 26.3% (CI95%: 15.0%–42.0%) using antigen detection methods. The prevalence of Cryptosporidium in HIV patients was significantly associated with the country of study. Also, there were statistical differences between the diarrhea, CD4 < 200 cells/mL, and antiretroviral therapy risk factors with Cryptosporidiosis. Thus, Cryptosporidium is a common infection in HIV-positive patients, and safe water and hand-hygiene should be implemented to prevent cryptosporidiosis occurrence in these patients.

Cystoisospora belli infections in humans: the past 100 years

Cystoisospora belli is a coccidian parasite of humans, with a direct fecal-oral transmission cycle. It is globally distributed, but mainly found in tropical and subtropical areas. Many cases of C. belli infections have been reported in patients with HIV, and in patients undergoing immunosuppressive therapy for organ transplants or those treated for tumours worldwide. Unsporulated or partially sporulated oocysts of C. belli are excreted in feces. When sporulated oocysts in contaminated water or food are ingested, asexual and sexual stages of C. belli are confined to the epithelium of intestines, bile ducts and gallbladder. Monozoic tissue cysts are present in extra-intestinal organs (lamina propria of the small and large intestine, lymph nodes, spleen, and liver) of immunosuppressed humans. However, a paratenic host has not been demonstrated. Cystoisospora belli infections can be persistent, lasting for months, and relapses are common; the mechanism of relapse is unknown. Recently, the endogenous stages of C. belli were re-examined and attention was drawn to cases of misidentification of non-protozoal structures in the gallbladder of patients as C. belli. Here, we review all aspects of the biology of C. belli, including morphology, endogenous stages, prevalence, epidemiology, symptoms, diagnosis and control.

Chronic Cystoisospora belli infection in an HIV/AIDS patient treated at the specialized assistance service in Porto Velho County - Rondônia

Cystoisospora belli infection manifests as diarrhea, and can potentially progress to malabsorption in HIV patients. Here, we report a case of C. belli infection in an HIV/AIDS patient with chronic diarrhea symptoms for at least 2 years. Coproscopic analyses based on direct technique and modified Ziehl-Neelsen technique without a commercial kit were performed. The current case report highlights the protocol to be adopted in coproscopic analyses applied to HIV patients. The importance of including the appropriate parasitological testing of patients with chronic intestinal isosporiasis in parasitological test routines must be considered.

Opportunistic and non-opportunistic intestinal parasites in HIV/ AIDS patients in relation to their clinical and epidemiological status in a specialized medical service in Goiás, Brazil

Patients infected with the Human Immunodeficiency Virus (HIV) often have opportunistic infections, among which strongyloidiasis and coccidiosis are the most common parasitic infections that aggravate their health status. This study examined the prevalence of intestinal parasites, particularly of Strongyloides stercoralis and intestinal coccidia in patients with the Human Immunodeficiency Virus (HIV)/ Acquired Immunodeficiency Syndrome (AIDS) who were treated at the Specialized Assistance Service (SAE) of Jataí, State of Goiás, Brazil, and analyzed its correlation with clinical, laboratory, and socio-epidemiological parameters. A total of 270 stool samples were analyzed by the Lutz technique, Rugai's method, Agar Plate Culture, Ritchie's method and specific staining, Ziehl-Neelsen modified technique, Kinyoun's method and the rapid safranin method. The prevalence of intestinal parasites was 28.88% including 3.8% of S. stercoralis, Cryptosporidium sp. and Cystoisospora belli. There was a significant positive correlation between intestinal parasites and the clinical status and the use of antiretroviral therapy (ART), smoking, CD4+ lymphocyte counts and sexual orientation. In conclusion, the widespread use of antiretroviral therapy and health assistance contributed to the low prevalence of S. stercoralis and coccidiosis in patients with HIV/ AIDS who were followed up at the SAE.

Prevalence and genetic characterization of Cryptosporidium spp. and Cystoisospora belli in HIV-infected patients

Cryptosporidium spp. and Cystoisospora belli are monoxenic protozoa that have been recognized as the causative agents of chronic diarrhea in immunocompromised individuals, especially HIV-infected subjects. The objective of this study was to evaluate the frequency of these intestinal protozoa in HIV-positive patients in the Triângulo Mineiro region of Brazil and to correlate the presence of these infections with clinical, epidemiological and laboratory data of the patients. Oocysts were detected in stool samples of 10 (16.9%) of the 59 patients studied, while Cryptosporidium spp. were present in 10.1% (6/59) and C. belli in 6.7% (4/59). The frequency of these parasites was higher among patients with diarrheic syndrome and CD4+ T lymphocyte counts < 200 cells/mm 3 , demonstrating the opportunistic characteristic of these infections. A significant association was observed between the lack of adherence to antiretroviral therapy and the presence of Cryptosporidium spp. and/or C. belli. Parasitism with Cryptosporidium spp. was more frequent in February and April, the months following the period of high rainfall. The same was not observed for C. belli. Genetic characterization of two isolates led to the identification of Cryptosporidium parvum, one of the main species associated with the zoonotic transmission of cryptosporidiosis.

Common variable immunodeficiency and isosporiasis: first report case

We report a severe case of diarrhea in a 62-year-old female HIV-negative patient from whom Giardia lamblia and Isospora belli were isolated. Because unusual and opportunistic infections should be considered as criteria for further analysis of immunological status, laboratory investigations led to a diagnosis of common variable immunodeficiency (CVID). This is the first reported case of isosporiasis in a patient with CVID and illustrates the importance of being aware of a possible link, particularly in relation to primary immunodeficiency.

Efficiency of diagnostic methods for correlation between prevalence of enteric protozoan parasites and HIV/AIDS status--an experience of a tertiary care hospital in East Delhi

Since the beginning of the AIDS pandemic, opportunistic infections have been recognized as common complications of HIV infection. Enteric protozoan parasitic infections are one of the leading causes of morbidity and mortality in HIV infected patients. The present study is, therefore, aimed to determine the prevalence of these parasites and study their association with immune status in HIV patients with emphasis on the correlation between various diagnostic techniques to give an accurate diagnosis to avoid empirical treatment. This prospective study, carried out between November 2009 and May 2010 included all HIV seropositive patients presenting with diarrhea to the ART center. A total of 64 stool samples were analyzed by wet mount examination, three different staining techniques, and antigen detection by ELISA for various enteric protozoan infections. Total prevalence of enteric protozoan parasites was 30%. Among the total cases, Cryptosporidium was seen in 12% cases followed by Giardia, E. histolytica and Isospora belli. The maximum diagnostic yield for coccidian parasites was with safranin-methylene blue staining technique. Parasitic burden contributes towards early morbidity in HIV infection. This study provides important information about prevalence of intestinal protozoan parasites in HIV infection. A combination of procedures should be carried out for the screening of stool specimens of HIV patients for better diagnosis and management.

Polymorphisms in the 18S rDNA gene of Cystoisospora belli and clinical features of cystoisosporosis in HIV-infected patients

Intraspecific variability among Cystoisospora belli isolates and its clinical implications in human cystoisosporosis have not been established. In this study, the restriction fragment length polymorphisms in a 1.8-kb amplicon of the small subunit ribosomal DNA (SSU rDNA) of the parasite was investigated in 20 C. belli-positive stool samples obtained from 15 HIV-infected patients. Diarrheic syndrome was observed in all patients with cystoisosporosis and the number of diarrheic episodes per patient during hospitalization ranged from 1 to 26 (mean of 9.64 ± 9.30), with a mean duration of 2 to 12 days (mean of 5.90 ± 3 days). Three restriction profiles (RF) were generated with MboII digestion, which were named RFI, RFII, and RFIII. Two isolates obtained from a patient with extraintestinal cystoisosporosis showed distinct restriction profiles with MboII. This study demonstrates that patients can be infected with different C. belli genotypes, and this information may be useful for identifying new C. belli genotypes infecting humans.

Etiological agents of diarrhea in patients infected by the human immunodeficiency virus-1: a review

Despite the importance of understanding the epidemiology of agents responsible for infectious diarrhea in human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) population, the number of articles about this subject is relatively few. The current article summarizes published data on bacterial, fungal, viral and parasitic enteropathogens in the HIV/AIDS seropositive subjects in different countries, regions and localities. In general, there is a great difference in the frequencies of etiological agents due to factors which include immune status, geographical location, climate and socioeconomic conditions. It is important to stress that a great prevalence of infection by emergent agents has been reported in the more advanced stages of AIDS. Therefore, to establish specific treatment depends directly on knowledge of these agents and risk factors associated to their distribution. Moreover, the colonization by potential pathogenic agents verified in these individuals is high thus implicating that they act as carriers. Finally, public health measures of control and prevention must take into consideration the regional previously identified enteropathogens, especially in areas where HIV prevalence is high.

Risks of recreational exposure to waterborne pathogens among persons with HIV/AIDS in Baltimore, Maryland

OBJECTIVES

We assessed the prevalence of recreational activities in the waterways of Baltimore, MD, and the risk of exposure to Cryptosporidium among persons with HIV/AIDS.

METHODS

We studied patients at the Johns Hopkins Moore Outpatient AIDS Clinic. We conducted oral interviews with a convenience sample of 157 HIV/AIDS patients to ascertain the sites used for recreational water contact within Baltimore waters and assess risk behaviors.

RESULTS

Approximately 48% of respondents reported participating in recreational water activities (fishing, crabbing, boating, and swimming). Men and women were almost equally likely to engage in recreational water activities (53.3% versus 51.3%). Approximately 67% (105 of 157) ate their own catch or that of friends or family members, and a majority (61%, or 46 of 75) of respondents who reported recreational water contact reported consumption of their own catch.

CONCLUSIONS

Baltimoreans with HIV/AIDS are engaging in recreational water activities in urban waters that may expose them to waterborne pathogens and recreational water illnesses. Susceptible persons, such as patients with HIV/AIDS, should be cautioned regarding potential microbial risks from recreational water contact with surface waters.