Human Cryptosporidiosis and Drinking Water: Looking Beyond HIV

Abstract

Cryptosporidium is an obligate intracellular apicomplexan parasite, responsible for significant morbidity and mortality in both humans and animals. It causes protracted and life-threatening diarrhea in HIV-infected individuals, along with some extra-intestinal symptoms. It also causes infection in other immunocompromised hosts like organ transplant recipients, patients with hematological malignancies, though there are fewer reports on this issue. Cryptosporidial infection is transmitted through feco-oral route by contaminated food and water. Oocyst of Cryptosporidium species is highly resistant to common water disinfection procedures, which has led to waterborne Cryptosporidium outbreaks, in both large and small communities. UV radiation, flocculation, sedimentation, and filtration are efficient against water contamination by cryptosporidial oocysts. Diagnosis of the parasite is based mainly on acid-fast staining, fluorescent stains like auramine-carbolfuchsin stain, ELISA of specific antigens, as well as antibodies, and polymerase chain reaction. The principle defense mechanism against Cryptosporidium sp. is cell-mediated immunity, particularly macrophage activation by CD4 ? T cells-derived cytokines. Th1 response assists in developing resistance to infection, whereas activation of Th2 cells results in increased parasite survival and exacerbation of lesions, due to macrophage suppressive action of Th2 cytokines, or during recovery stages of the infection. Immune restoration is very important for treatment. Nitazoxanide and Paramomycin are the mainstay of therapy, however complete elimination of the parasite is difficult.

Genotyping ofCryptosporidiumSpecies and Their Clinical Manifestations in Patients with Renal Transplantation and Human Immunodeficiency Virus Infection

“…It has been well documented in previous studies that patients having lower CD4 count are at higher risk of cryptosporidiosis. Chronic cryptosporidiosis generally occurs in patients with CD4 counts below 200 cells/cumm [ 18 ], and patients with CD4 count below 50 cells/cumm suffer from severe infections [ 3 ]. In fact, several studies have documented a correlation between CD4 count <200 cells/cumm and symptomatic cryptosporidiosis, in HIV patients [ 11 , 17 ].…”

“…An inverse relationship between occurrence of cryptosporidiosis and CD4 T cell count has been well documented in many studies in patients with AIDS. HIV/AIDS patients having lower CD4 count (<200 cells/cumm) are at higher risk of cryptosporidiosis [ 4 , 17 ], with severe infections below 50 cells/cumm CD4 count [ 3 , 18 ]. Such studies are scanty among RT recipients.…”