human inmmunodeficiency virus ( hiv ) infection is the most common cause for immunodeficiency state worldwide , with the hallmark of infection being depletion of cd4 + t lymphocytes , the essential components of the cell - mediated immunity . enteric protozoan parasites remain the most commonly encountered parasitic diseases and continue to cause significant morbidity and mortality . several secondary gastrointestinal ( git ) infections including bacterial , viral , parasitic , and fungal diseases besides primary hiv enteropathy is known . opportunistic protozoal infections that infect git most commonly and cause diarrhea in hiv - infected patients are cryptosporidium parvum , microsporidia , and isospora belli . immunosuppressed hosts are more likely to acquire infection after exposure and have more severe disease once the infection is established . they have disseminated infection rather than localized infection , and are unable to clear parasites , thereby , becoming chronic carriers . developing an infection with enteric protozoan parasites is dependent on absolute cd4 + cell counts , with lower counts associated with more severe , more atypical disease , and a greater risk of disseminated disease . we present histopathological features in a patient , where all three parasitic infections coexisted in hiv - infected patient , who was under anti - tubercular therapy ( att ) in addition to antiretroviral therapy ( art ) and herpes zoster infection being treated by acyclovir . a 43-year - old male was diagnosed in november 2008 as hiv - positive and was on regular art . he was admitted to hospital with complaint of passing loose stools 8 - 10 times per day since 1 month without associated pain abdomen , passage of blood or mucus in stool . it was diagnosed as cryptosporidial diarrhea on stool examination and he was treated with nitrazoxamide successfully . he was a documented case of disseminated tuberculosis since august 2010 and was on att . presently , he is also a patient of herpes zoster ( t6-t10 dermatome ) and is on acyclovir therapy . on general physical examination , he was found to be a thinly built , well oriented , afebrile with a supine blood pressure of 90/66 mmhg and a regular pulse rate of 88/min . ultrasonography of abdomen and pelvis showed calcified areas in segment vii of liver and multiple hypoechoic focal lesions ( ? granulomas ) . the laboratory investigations revealed hemoglobin-10.9 g / dl , total leucocytic count -4,200/l , differential leucocytic count was lymphocytic predominant ( 54% ) , and a platelet count of 1.5 lakh/l . his absolute cd4 + t lymphocyte count was 219 cells/l and viral load was less than 400 copies / ml . his liver and renal function tests and urine examination were essentially normal . upon stool examination no ova , cyst , acid - fast bacilli , or any other organism was discerned . histopathological examination of biopsy from second part of duodenum revealed mild atrophy in the form of blunting , shortening , and fusion of villi with crypt elongation at places . a focal disorganization of the epithelium , loss of nuclear polarity , cell crowding , and cell vacuolation was seen [ figure 1a ] . these organisms were seen in the basal part of cytoplasm below and around the nucleus . focally on luminal surface of occasional enterocytes , small bluish intracellular but extracytoplasmic round to oval amphophilic structures resembling cryptosporidia were seen . also noted were foci of occasional enterocytes containing intracytoplasmic vacuoles with small , round to oval , bluish supranuclear refractile spores resembling microsporidia [ figure 1b ] . special histochemical stains to identify the parasites done were  brown  bren modification of gram stain , pas , masson 's trichrome , toluidine blue [ figure 1-d ] , giemsa , modified acid fast , and gomori 's methanamine silver ( gms ) stains . a histopathology opinion of enteritis due to triple infection by isosporidia , cryptosporidia , and microsporidia was offered . the isospora sporozoites are elongated banana - shaped and microsporidia are small dot like 1 - 1.5- basophilic structures ( h and e stain 200 ) masson 's trichrome stain brings out the trophozoites of isospora around the nucleus of the epithelial cells in the duodenal villi ( 200 ) high - power view of the duodenal villus epithelial cells showing presence of isospora trophozoites ( masson 's trichrome 400 ) toludine blue stain reveals presence of extracytoplasmic surface cryptosporidia over the duodenal villus ( 200 ) based on histopathology report , patient was put on tablets niazoxanide , septran , cifran , and fluconazole . he has since improved and is under regular follow - up in the outpatient department and art center of the hospital . opportunistic infections are generally restricted to severely immunosuppressed individuals and are considered aids - defining illnesses in hiv - infected patients , as they almost always occur when the cd4 + t - cell count falls below 200 cells/l . since many of these infections are treatable , an early and accurate diagnosis is important . this can be accomplished by a variety of methods such as direct demonstration of the parasite , spores and by serological tests to detect antigen and/or specific antibodies . for example , antibody response may be poor in these patients and therefore immunodiagnostic tests have to be interpreted with caution . cryptosporidial disease commonly caused by c. parvum , has a predilection for the proximal small bowel , resulting in nonspecific thickening of the duodenum , jejunum , and proximal ileum . cryptosporidium species other than c. parvum and c. hominis were identified in 9.4% of the patients analyzed in a european study in hiv - infected . in untreated hiv infected patients with cd4 + t cell counts of < 300/l , the incidence of cryptosporidiosis is approximately 1% per year . laboratory diagnosis is made by demonstrating oocysts in the specimens using modified acid - fast stain . cryptosporidial infection is confined to luminal surface of enterocytes from base of crypts to the tips of the atrophied villi . villus atrophy and crypt hyperplasia are nonspecific and can be present in varying degrees as in the case of microsporidiosis and isosporidiasis . cryptosporidium characteristically is intracellular but extracytoplasmic and bulges from the apical surface of the epithelium . therapy is predominantly supportive , and marked improvements have been reported in the setting of effective art . microsporidia on the other hand are small , unicellular , obligate intracellular parasites that reside in the cytoplasm of enteric cells . the clinical manifestations are similar to those for cryptosporidia and include abdominal pain and diarrhea . the small size of the organism may make it difficult to detect ; however , diagnosis is made by demonstrating spores in stool specimens by modified trichrome stain or in the tissue biopsy specimen [ figure 1c ] . microsporidia - infected bowel displays villous atrophy and pleomorphism , crypt hyperplasia , and increased number of intraepithelial lymphocytes . the tip of infected villus appears as progressively more disorganized aggregates of crowded cells ( piling up ) that are undergoing degeneration and necrosis . . definitive diagnosis may require electron - microscopic examination of a stool specimen , intestinal aspirate , or intestinal biopsy specimen . isosporiasis caused by i. belli oocysts ingestion of which produces protracted and sometimes a profuse diarrhea . upper gi endoscopy with biopsy is diagnostic method of choice , if oocysts are not visualized in stool . histopathological changes are more extensive than due to mere presence in the infected cells , suggesting that the parasite releases toxic agents , which cause hypersensitivity reaction . parasite is intracellular in location , relatively large in size , and is surrounded by parasitophorous vacuole making its identification easy . the important distinction is that infection with isospora is relatively easy to treat with trimethoprim - sulfamethoxazole . to the best of our knowledge , it is the first case being reported in india with triple infection diagnosed on tissue biopsy , when the stool examination did not reveal the parasites . identification of parasites causing intestinal infections helped in specific therapy limiting the morbidity and providing symptomatic motor relief . the take - home message from this presentation to our young colleagues and clinicians is that in a known immunosurveillance case , one must look out for additional tissue pathogens for timely and correct therapy .
enteric protozoan parasites remain the most commonly encountered parasitic diseases in hiv infected patients . 
 opportunistic protozoal infections that infect git most commonly and cause diarrhea in hiv - infected patients are cryptosporidium parvum , microsporidia and isospora belli . developing an infection with enteric protozoan parasites is dependent on absolute cd4 + cell counts , with lower counts associated with more severe , more atypical disease , and a greater risk of disseminated disease . 
 we present histopathological features in a patient , where all three parasitic infections co - existed in hiv infected patient , who was under antitubercular therapy in addition to antiretroviral therapy and herpes zoster infection being treated by acyclovir .