Indian J Med Res 130, July 2009, pp 63-66
Opportunistic parasitic infections in HIV/AIDS patients presenting
with diarrhoea by the level of immunesuppression
S.V. Kulkarni, R. Kairon, S.S. Sane, P.S. Padmawar, V.A. Kale, M.R. Thakar
S.M. Mehendale & A.R. Risbud
National AIDS Research Institute, (ICMR), Pune, India
Received November 28, 2007
Background & objectives: Enteric parasites are major cause of diarrhoea in HIV infected individuals.
The present study was undertaken to detect enteric parasites in HIV infected patients with diarrhoea at
different levels of immunity.
Methods: The study was carried out at National AIDS Research Institute, Pune, India, between March
2002 and March 2007 among consecutively enrolled 137 HIV infected patients presenting with diarrhoea.
Stool samples were collected and examined for enteric parasites by microscopy and special staining
methods. CD4 cell counts were estimated using the FACS count system.
Results: Intestinal parasitic pathogens were detected in 35 per cent patients, and the major pathogens
included Cryptosporidium parvum (12%) the most common followed by Isospora belli (8%), Entamoeba
histolytica/Enatmoeba dispar (7%), Microsporidia (1%) and Cyclospora (0.7%). In HIV infected patients
with CD4 count < 200 cells/µl, C. parvum was the most commonly observed (54%) pathogen. Proportion
of opportunistic pathogens in patients with CD4 count <200 cells/µl was significantly higher as compared
with other two groups of patients with CD4 count >200-499 and ≥ 500 cells/µl (P=0.001, P=0.016)
respectively.
Interpretation & conclusions: Parasitic infections were detected in 35 per cent HIV infected patients
and low CD4 count was significantly associated with opportunistic infection. Detection of aetiologic
pathogens might help clinicians decide appropriate management strategies.
Key words Diarrhoea - HIV - opportunistic parasites
Cryptosporidium parvum, Cyclospora cayetanensis,
Isospora belli and Microsporidia are documented in
patients with AIDS4. Non opportunistic parasites such
as Entamoeba histolytica, Giardia lamblia, Trichuris
trichiura, Ascaris lumbricoides, Strongyloides
stercoralis and Ancylostoma duodenale are frequently
encountered in developing countries but are not
currently considered opportunistic in AIDS patients5.
In immunocompromised patients, the intestinal
Gastrointestinal infections are very common in
patients with HIV infection or AIDS1. Diarrhoea is
a common clinical presentation of these infections. Reports indicate that diarrhoea occurs in 30-60 per cent
of AIDS patients in developed countries and in about
90 per cent of AIDS patients in developing countries2.
The aetiologic spectrum of enteric pathogens causing
diarrhoea includes bacteria, parasites, fungi and
viruses3. The presence of opportunistic parasites
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INDIAN J MED RES, JULY 2009
opportunistic parasites probably play a major role in
causing chronic diarrhoea accompanied by weight
loss6. The incidence and prevalence of infection with
a particular enteric parasite in HIV/AIDS patients is
likely to depend upon the endemicity of that particular
parasite in the community7. C. parvum, I. belli and E.
histolytica have been reported as the most frequently
identified organisms in HIV infected individuals with
diarrhoea from India and other parts of the world 8-15. The present study was undertaken to study the
prevalence of enteric parasites causing diarrhoea and
their association with immune status in HIV infected
patients in Pune, India.
Material & Methods
The study was carried out in seven clinics set up by
the National AIDS Research Institute (NARI), India,
in the city of Pune, Maharashtra. Two of these seven
clinics are located at two tertiary care hospitals, two in
municipal corporation dispensaries, two are HIV referral
clinics on NARI campus and one is set up in the red
light area of Pune. STD and HIV diagnostic services,
care and support services to HIV infected patients are
provided at these clinics. During March 2002 to March
2007 consecutive HIV infected patients presenting with
diarrhoea at these seven clinics were considered for
inclusion in the study. Study patients were interviewed
using the structured questionnaire and information
was obtained on demographic characteristics, present
and past history of diarrhoea and antibiotic treatment.
Diarrhoea was defined as two or more liquid or three or
more soft stools per day. Patients already on antibiotic
treatment were excluded from the study. A total of 137
patients were enrolled in the study.
Blood samples (plain & EDTA) 5 ml each were
obtained from enrolled patients. Serum samples were
used for HIV testing. HIV serostatus of the patients was
determined by using commercially available ELISA
antibody tests (Genetic system, Biorad Labs, USA
and Tridot, J Mitra & Co., New Delhi) using National
AIDS Control Organisation (NACO) recommended
algorithm16.
CD4 cell counts were measured by using a FACS
count system (Becton Dickinson, Singapore BD).
Patients were categorized by their immune status
according to the 1993 – revised classification system
for the HIV infection by CD4 T-cell categories17.
Stool examination: Stool specimens were collected
according to the WHO standard procedure and examined
microscopically following direct and formalin-ether
concentration methods18. Stool samples were collected
at home in labelled, leak proof, clean sterile plastic
containers and then submitted at NARI clinics and
were transported to the laboratory within three hours
of collection. The stool samples were fixed in 10 per
cent formalin saline, concentrated using formyl/ ethyl
acetate and examined through direct observation in
saline (0.85% NaCl solution). Lugol’s iodine was used
for the detection of ova, larvae, trophozoites and cysts
of intestinal parasites. E. histolytica and E. dispar was
studied by light microscopy (Carl Zeiss Inc, USA) by
trained observers. Smears of direct and concentrated
specimens were examined by modified acid fast
staining for C. parvum, I. belli and Cyclospora18,19.
Modified trichrome stain (Hi-media laboratories,
India, Qualigens Fine Chemicals, India) was used for
detecting Microsporidia20. The study was approved by
institutional ethics committee.
Statistical analysis: Data were analysed using SPSS
software version 14.0 (SPSS Inc, USA). The proportions
of opportunistic pathogens were compared between the
CD4 groups by using Z test.
Results & Discussion
Of the 137 patients, 100 (73%) were males and 37
(27%) females. The mean age of the male and female
patients was 34.6 ± 7.51 and 33.2 ± 9.95 yr respectively.
The study population consisted of 19 patients with
CD4 count > 500 cells/µl, 53 patients with CD4 count
200-499 cells/µl and 65 patients with CD4 count < 200
cells/µl. Enteric parasites were detected in 48 (35%)
stool samples, of which 30 (62.5%) were opportunistic
and 18 (37.5%) were non opportunistic. Among
the 18 patients with non opportunistic parasites,
nine had E. histolytica/E. dispar, four had Ascaris
lumbricoides, three had Ancylostoma duodenale and
two had Hymenolepsis nana. Opportunistic parasites
were C. parvum (16), I. belli (11), Microsporidia (2)
and Cyclospora (1). Overall, Cryptosporidium (12%)
was the most frequently encountered pathogen in the
study population followed by Isospora (8%) and E.
histolytica/E. dispar (6.6%).
Among the 65 patients with CD4 count < 200
cells /µl, parasites could be identified in 30 (46%)
patients and opportunistic parasites were detected in
as many as 24 (37%) patients. Cryptosporidium (13)
was the most common pathogen followed by I.belli
(8), Microsporidia (2) and Cyclospora (1). Of the
53 (39%) patients with CD4 count 200-499 cells/µl,
KULKARNI et al: INTESTINAL PARASITE IN HIV INFECTED PATIENTS WITH DIARRHOEA
parasite could be identified in 12 (23%) patients, and
opportunistic parasites in 5 patients only. E. histolytica/
E. dispar (4) was the most common parasite followed
by Cryptosporidium (3). The other parasites detected
were I.belli (2), A. duodenale (2) and A. lumbricoides
(1). Parasites were detected in only 6 patients with
CD4 count >500 cells/µl, of which H. nana was
detected in 2, and E. histolytica/E. dispar, A. duodenale
and A. lumbricoides were detected in 1 patient each.
Interestingly, I. belli was detected in one patient. The
proportion of opportunistic pathogens in patients with
CD4 count <200 cells/µl was significantly higher than
that in the other two groups of patients with CD4 count
> 200 cells/µl (P=0.001 and P=0.016).
Numerous opportunistic infections occur in
HIV infected patients, due to downregulation of the
immune system. Gastrointestinal parasitic infection
is a universally recognized problem in these patients.
These infections largely present with diarrhoea leading
to life threatening complications20. In the present
study, enteric parasites were detected in 35 per cent of
HIV infected patients with diarrhoea. Various studies
from India and other countries have reported a high
prevalence of intestinal parasite, ranging from 30 to
60 per cent10,14,21-23. Almost half of the patients with
CD4 count less than 200 cells/µl were found to have
gastrointestinal parasitic infections and a majority of
which were opportunistic parasites (37%). Among
the opportunistic parasites, C. parvum (54%) was the
predominant pathogen. Several studies from India
and other parts of the world also have reported the
same12,24-26. The prevalence of opportunistic parasites
in patients with CD4 count 200-499 cells/µl was found
to be 9 per cent.
Thus, like many other studies, we also found
that infections with opportunistic pathogens were the
leading cause of diarrhoea in HIV infected individuals,
especially, in subjects with advanced disease. C.
parvum and I. belli, were the most common pathogens. Among the non opportunistic pathogens E. histolytica/
E. dispar seemed to contribute significantly has shown
earlier12,20,22,24,25. Similar to other reports, Microspordia
and Cyclospora were detected in a few patients
only10, 27-29.
The reported prevalence of non opportunistic
parasites varied from 5-30 per cent in HIV infected
patients5,9. In the present study, non opportunistic
parasites were detected in 13 per cent patients across
different CD4 groups, thus, highlighting the need for
65
early detection and treatment of such infections among
HIV-infected patients to reduce the morbidity.
There was some limitations in our study. The study
was done on a small sample size as a majority of the
patients who came to NARI clinics were referred from
the general practioners or from primary or secondary
care centers. Patients were also referred from Voluntary
Counseling & HIV Testing centers. Majority of the
patients seen at these centers had already received
antibiotics prior to their visit and therefore the number
of symptomatic patients was less.
In conclusion, intestinal parasitic infection
caused diarrhoea in 35 per cent of the study subjects.
Most of the infections in patients with CD4 count
<200 cells/µl were due to opportunistic pathogens.
The results of our study highlight the importance of
evalution of HIV infected individuals with diarrhoea
for intestinal parasitic infections which may help in
better management of these patients. A etiology of
diarrhoea could not be determined in 65 per cent of the
study patients, suggesting a need for a comprehensive
aetiological studies covering bacterial, fungal, viral,
and parasitic causes of diarrhoea among HIV infected
patients in India.
Acknowledgment
Authors thank all the NARI Clinic staff for providing support
for recruitment of patients and collection of samples, and also
acknowledge the Director, NARI for extending support for the
study.
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Reprint requests: Dr Sangeeta V. Kulkarni, Department of Microbiology, National AIDS Research Institute (ICMR)
Pune 411 026, India
e-mail: [email protected], [email protected]