Cryptosporidiosis, whether it is more prevalent in Southern India.

Cryptosporidium species is identified as an important cause of morbidity in children and adults. Prevalence rate as reported from various studies in India is much lower when compared to developed word. Present study was designed to analyze the prevalence of cryptosporidiosis in West Godavari District, Andhra Pradesh. Stool samples from 306 patients suffering with gastrointestinal symptoms were examined for the presence of Cryptosporidium oocysts. A higher prevalence (25%) was found when compared to reports from north east and western India. Cryptosporidium was prevalent in 35-36% of adults, 17% of children and 20% of infants.

THE STUDY

Cryptosporidium reported by Tyzzer in 1907[1] and well-known to veterinarians since 1953, has gained recognition as a human pathogen since 1976.[2] The acquired immune deficiency syndrome pandemic has brought Cryptosporidium to the forefront as an important pathogen in immunocompromised persons.[34] Cryptosporidium species is now commonly identified in cases of acute, self-limited diarrheal illness in immunocompetent hosts in both developed[56] and developing[78] nations. The seroprevalence of Cryptosporidium among patients suffering with diarrhea is reported as high as 90% from Brazil and 50% from China.[9] In the developing world, the association of Cryptosporidium with both acute and persistent diarrhea among immunocompetent children has been reported as 29.6%.[10] On the other hand, the prevalence as reported from India is low e.g., 1.3% from Northern India,[11] 4.5% from the eastern part of the country (West Bengal),[12] 5.5% from South to West (Mumbai)[13] and 13.1% from South India.[14] In a recent study from Hyderabad prevalence was reported to be as low as 2.99% in children and 0.12% in adults.[15]

The present study was designed to assess the prevalence of cryptosporidiosis among cases from West Godavari district. Patients belonging to West Godavari district suffering from diarrhea or other gastrointestinal symptoms who attended ASRAM Hospital, ELURU from November 2006 to October 2007 were included in the present study. Study population included both out-patients and inpatients from different clinical departments selected on random bases. Permission was taken from Institutional Human Ethical Committee for commission of this study. All the stool samples were examined using saline and iodine wet mounts for the presence of protozoal cysts, trophozoites, helminthic ova, larvae, pus cells, macrophages and red blood cells. For detection of Cryptosporidium oocysts, samples were concentrated by Sheather sucrose floatation method.[16] Smears prepared from concentrated samples were fixed, air-dried and stained with modified Ziehl-Neelsen method (Kinyoun stain).[17] Oval or round acid fast bodies (dark pink) 4-5 μm in size were taken as oocysts of Cryptosporidium. All slides were examined by two observers. All the patients carrying Cryptosporidium oocyst in their stool samples were also subjected to human immunodeficiency virus (HIV) screening test. The socio-economic status was evaluated based on Kuppuswamy's socio-economic status scale-updating for 2007[18] with a little modification that instead of dividing study population into five groups we divided it into three groups by merging upper and upper middle into high and upper lower and lower in low socio-economic group.

A total of 306 samples could be collected (192 males and 114 females). Out of 306 cases 15% (45/306) were in the age group 0-1 year, 19% (58/306) in the age group 1-5 year, 02% (6/306) in 5-12 year, 10% (30/306) in 12-18 year, 38% (117/306) in 18-40 year and 16% (50/306) in >40 years. 27% patients (84/306) were positive for one or more parasites. Oocysts of Cryptosporidium spp. were detected in 25% (78/306) patients. ([Adults 76% [59/78], Children 13% [10/78] and Infants 11% [9/78]]). Prevalence in the age group 0-1 year was 20% (9/45), in 1-5 year 17% (10/58), in 18-40 year 35% (41/117) and above 40 it was 36% (18/50). We could not detect Cryptosporidium in the age group 5-12 and 5-18 year. Out of 78 cases positive for cryptosporidium oocyst, 69% (54/78) were males and 31% (24/78) were females. Prevalence in male was 28% (54/192) and in females it was 21% (24/114). Among all the cases included in the study, 180 were from low, 90 from middle and 36 from high socio-economic group. The prevalence rate was 27% (48/180) in low, 20% (18/90) in the middle and 33% (12/36) in high socio-economic group. Out of 78 cases positive for cryptosporidium 11 were positive for HIV by the screening test (HIV Tridot, J. Mitra and Co Pvt. Ltd.). Other parasites detected were Isospora belli 5% (14/306), Taenia spp. 3% (9/306), Strongyloides stercoralis 2% (5/306) and Entamoeba histolytica 1% (3/306). Co-infection was found in 8% (24/306) cases (Cryptosporidium with Taenia spp. 2% [6/306], Cryptosporidium with I. belli 4% [13/306] and Cryptosporidium with I. belli and S. stercoralis 2% [5/306]).

CONCLUSIONS

Prevalence of human cryptosporidiosis varies widely in different parts of the world. Recurrent Cryptosporidium infection and relapsing diarrhea associated with it was found to be common in North Eastern Brazil.[19] A review of 78 reports showed Cryptosporidium infection in immunocompetent persons with diarrhea in 2.1% of industrialized and 6.1% of developing countries respectively.[20] Seroprevalence is much higher. 50% of children in China and more than 90% of children in Brazil had serologic evidence of cryptosporidial infection.[9] In the developing countries, the disease is endemic.[78] In India, the reported prevalence differs in various part of the country. In South India, Cryptosporidium spp. was detected in 13.1% of children with diarrhea and 9.1% of age matched controls.[14] Reports from West Bengal and Mumbai showed the parasite to be prevalent in 4.45% and 5.5% of children with diarrhea respectively.[1213] A lower prevalence rate of 1.3% was reported from North India.[11] In the present study, Cryptosporidium was prevalent in 35-36% of adults 17% of children and 20% of infants. It seems that these parasites have a tendency to colonization in adults. We could not find any positive case in the age group 5-12 year and 12-18 years. The reason may be that only a small no of cases (total 36) attended the hospital in this age group. 11 cases positive for Cryptosporidium oocyst were also positive for HIV. This finding is in favor of the previous reports that Cryptosporidium is an opportunistic pathogen.

We conclude that the prevalence of Cryptosporidium among cases suffering with diarrhea is remarkably high in India at least in the southern part of the country. In our study, we examined concentrated samples for detection of Cryptosporidium oocyst. It may have contributed to a higher rate of detection. The difference in prevalence in various socio-economic groups was statistically not significant. (P = 0.256). The prevalence in male and female was also statistically not significant (P = 0.113). All the findings so far reported are from hospital based studies. In spite of the increasing numbers of HIV infected patients and low standards of sanitation in the country, which predispose to Cryptosporidium infection, awareness regarding the disease continues to be low among microbiologists and clinicians. In order to understand the as yet undefined host parasite interaction, genetic and epidemiologic characterization of the neglected protozoon parasite Cryptosporidium, is needed.