Characterization of hepatitis E-specific cell-mediated immune response using IFN-gamma ELISPOT assay.

In developing countries, hepatitis E (HEV) and hepatitis A (HAV) are the major causes of acute viral hepatitis with similar feco-oral modes of transmission. In contrast to the high seroprevalence of hepatitis A infection, a low seroprevalence of HEV among children in endemic areas has been reported. These data suggest the possibility that silent HEV infection is undiagnosed by the current available methods. Many of the serological tests used for HEV diagnosis have poor specificity and are unable to differentiate among different genotypes of HEV. Moreover, the RT-PCR used for HEV isolation is only valid for a brief period during the acute stage of infection. Cell-mediated immune (CMI) responses are highly sensitive, and long lasting after sub-clinical infections as shown in HCV and HIV. Our objective was to develop a quantitative assay for cell-mediated immune (CMI) responses in HEV infection as a surrogate marker for HEV exposure in silent infection. Quantitative assessment of the CMI responses in HEV will also help us to evaluate the role of CMI in HEV morbidity. In this study, an HEV-specific interferon-gamma (IFN-gamma) ELISPOT assay was optimized to analyze HEV-specific CMI responses. We used peripheral blood mononuclear cells (PBMC) and sera from experimentally infected chimpanzees and from seroconverted and control human subjects to validate the assay. The HEV-specific IFN-gamma ELISPOT responses correlated strongly and significantly with anti-HEV ELISA positive/negative results (rho=0.73, p=0.02). Moreover, fine specificities of HEV-specific T cell responses could be identified using overlapping HEV ORF2 peptides.

Lyme disease surveillance in Maryland, 1992.

The incidence of Lyme disease (LD) reported to the Maryland Department of Health and Mental Hygiene during 1992 was 6.5/100,000 population, ranging from 29.3 cases/100,000 on the Eastern Shore (74.4% of all cases) to no cases in the mountains of western Maryland. Among the 317 reported patients, 44.4% gave a history of tick exposure and 78.9% had positive serologic test results. For the 187 (59.0%) patients meeting the Centers for Disease Control and Prevention (CDC) surveillance case definition, erythema migrans (EM) occurred in 69.5%, with arthritic (26.7%), neurologic (13.4%), and cardiac (2.1%) manifestations being less frequent. Patients not meeting the surveillance case definition were significantly more likely to have influenza-like symptoms, a smaller rash, and arthralgia. Patients meeting the CDC criteria were more likely to have an onset during the major transmission season in the summer (odds ratio (OR): 2.1; confidence interval (CI): 1.2 to 3.6) since this was the time when most (115/130) patients with EM were detected. Positive serologic results were more likely (OR: 2.2; CI: 1.2 to 4.2) in those not meeting the case definition. The treatment given to patients thought to have LD was almost always that recommended in the literature and there was no difference between treatment prescribed for patients meeting and those not meeting the case definition. These data show that physicians in Maryland are treating many patients for LD who are clinically diagnosed as having LD (e.g., febrile patients with flulike symptoms, patients with arthralgias or erythematous rashes < 5 cm in size) and who have positive serologic test results but who do not meet the CDC surveillance case definition. These patients and the large number of unreported patients being seen and treated for LD or tick bites must be added to the overall burden of LD in the state.

Murine malaria: cellular interactions in the immune response.

The cellular and humoral interactions that contribute to protective immunity in Plasmodium yoelii malaria were studied by adoptive transfer of selective cell populations or hyperimmune serum into sublethally irradiated syngeneic C57BL/6 mice. For some experiments pools of mononuclear spleen cells were depleted of T or B lymphocytes and cells that take up silica were inactivated by standard procedures. Unfractionated immune spleen cells, but not nonimmune spleen cells, protected recipients from lethal P. yoelii challenge. Analysis of the protective capacity of subpopulations of immune spleen cells showed that levels of immunity similar to those seen after transfer of unfractionated immune cells were present only in those instances where immune macrophages, i.e., cells not previously inactivated with silica, were transferred concomitantly with either immune T (supplemented with nonimmune B) or immune B (supplemented with nonimmune T) cells. The requirement for immune macrophages could not be met by transferring mononuclear cells from a nonimmune donor. The results support the hypothesis that an immune 5,000 R-radioresistant, silica-inactivated, non-T, non-B cell, probably a macrophage, must act in concert with immune T and B lymphocytes in the optimal expression of transferred immunity to P. yoelii.

Successful treatment of symptomatic Entamoeba polecki infection.

The second symptomatic case of Entamoeba polecki infection, the first to respond to therapy, is reported. The patient experienced intermittent episodes of abdominal cramps, diarrhea, nausea, and malaise associated with large numbers of E. polecki cysts in the stool. Following treatment with diloxanide furoate and metronidazole, all symptoms cleared and the parasite was no longer present in the stool.

Ultrasonographic resolution time for amebic liver abscess.

Hepatic ultrasonography not only can be used to detect amebic liver abscess, but can follow its resolution. Twenty-five patients with 32 abscesses had hepatic sonography performed repeatedly. Sonography clearly demonstrated abscesses of 1-22 cm; 19 patients (76%) had abscesses only in the right lobe of the liver, and 22 (88%) had solitary abscesses. Resolution time ranged from 2 months for the smallest abscess to 20 months for the largest. Four abscesses initially had a heterogenous partially solidified pattern. All abscesses healed completely, leaving normal hepatic sonographic patterns.

Characteristic sonographic pattern of schistosomal hepatic fibrosis.

The hepatic sonographic patterns from 50 patients undergoing operations for bleeding esophageal varices were compared with the interpretation of the histological findings in a hepatic wedge biopsy obtained during surgery. The sonographic pattern for schistosomiasis periportal fibrosis is characteristic and is not mimicked by other hepatic diseases we have studied. Sonography agreed with pathology in 44 out of 50 patients. Schistosomiasis could be separated from cirrhosis, as well as from combined lesions. Where there was a discordance, we believe that sonography gave a more accurate diagnosis.

Determinants of infection with schistosomiasis haematobia using logistic regression.

A population-based stratified random sample of 10,039 inhabitants of rural communities in Minya Governorate, Egypt, were evaluated for risk factors for Schistosoma haematobium infection using multivariate analysis. Data were obtained by personal interview recording demographics, information on exposure to canal water, history of infection, and other risk factors for infection and examining urine samples for S. haematobium ova. Logistic regression analysis was used to adjust for confounders while assessing the role of each risk factor for infection. Using logistic regression allowed detection of several confounders and interactions which influenced other independent variables. Differences in exposure patterns to canal water among age and gender subgroups explained only a small portion of the variation in infection rates, thus favoring the alternative explanation: development of age-acquired immunity. The association of age with reduced prevalence of S. haematobium was the only relationship increasing (odds ratio [OR] = 2.95-4.30) with logistic regression. Male gender was a risk factor for infection but did not increase with logistic regression (OR = 2.33-2.03). The protective effects of education, only noted in schoolage children (OR = 0.59-0.51), were believed to be due to a school-based screening and treatment program.

Hematuria and proteinuria as predictors of Schistosoma haematobium infection.

An investigation of a population-based stratified random sample of 11,970 inhabitants of Minya Governorate in Egypt included examining urine specimens for Schistosoma haematobium ova using the filtration technique and for hematuria and proteinuria using reagent strips. Age- and gender-specific sensitivity, specificity, predictive values, and likelihood ratios of reagent strip-detected hematuria and proteinuria as indicators of S. haematobium infection were assessed. Results showed that in this population with a 9.0% infection rate, sensitivity (from 45.9 to 70.9) and specificity (from 65.9 to 86.3) were much lower than in previous reports. The most clinically valuable parameters, positive predictive value (PPV), negative predictive value (NPV) and likelihood ratio (LR), were highest with the presence of hematuria > or = +++ and proteinuria > or = ++, especially in males less than 20 years of age. Using the LR allowed effective altering of the pretest probability of infection among age and gender subgroups. The study concluded that reagent strip-detected hematuria and proteinuria, although valuable, are less reliable predictors of S. haematobium within communities than previously reported and their usefulness is improved with stratification by age and gender. In addition, predictive values and likelihood ratios provide practical information for predicting the presence or absence of infection within population subgroups.

Grading of hepatic schistosomiasis by the use of ultrasonography.

Forty-three subjects with pure hepatic schistosomiasis having ultrasonographic assessment of periportal fibrosis were grouped according to the thickness of their portal tracts: grade I = 3-5 mm, grade II = greater than 5-7 mm, and grade III = greater than 7 mm. A history of hematemesis, blood transfusion, sclerotherapy, and lower limb edema correlated with the ultrasonographic grade of periportal fibrosis. With increasing grade, the average liver size was smaller and the average spleen size was larger, as determined by physical examination and by ultrasonography. Abnormalities in serum enzyme levels were more frequent in those with thicker portal tracts. Greater diameters of the portal and splenic veins and ultrasonographically detectable collateral blood vessels were associated with increasing thickness of portal tracts. The grade of endoscopically determined esophageal varices was highly correlated with the grade of periportal fibrosis. We concluded that this method of grading accurately reflects the hemodynamic changes and provides a good estimate of the clinical status of patients who have periportal fibrosis due to schistosomiasis mansoni. Where available, it should replace clinical grading based upon the liver and spleen size as detected by physical examination.

Effects of Fansidar on chloroquine-resistant Plasmodium falciparum in Pakistan.

Fansidar (SP), a combination of sulfadoxine and pyrimethamine, was evaluated for its usefulness as a curative agent for treating individual malaria patients and for reducing the community reservoir of Plasmodium falciparum in 4 villages near Lahore, Pakistan, where resistance of 4-aminoquinolines has recently been reported. Following the end of the major malaria transmission season, we carried out a month-long mass treatment campaign during which SP was given to all available villagers who had parasitemias detected during a concurrent house-to-house malaria blood film survey. Of the 82 falciparum patients followed for 14 days after SP treatment, 80 (97.5%) had parasites sensitive to the investigated drug. Parasitemia clearance time after SP was remarkedly short (1.25 +/- 0.53 days; mean +/- SD). However, we were unable to reduce the parasite reservoir of P. falciparum and P. vivax in these villages, probably because we treated only 337, about one-third, of the parasitemic patients. We conclude that SP is an effective drug for treating individual malaria patients from areas in Pakistan where 4-aminoquinoline-resistant parasites are present, but that more research is needed for assessing its usefulness in reducing community reservoirs of malaria.

Effects of chloroquine, amodiaquine and pyrimethamine-sulfadoxine on Plasmodium falciparum gametocytemia.

The effects of chloroquine, amodiaquine and pyrimethamine-sulfadoxine (SP) (Fansidar) on the infection rate and density of Plasmodium falciparum gametocytes were studied in 198 patients with falciparum malaria from an area in the Punjab where malaria is endemic but seasonally transmitted. One month following treatment of 100 patients, SP had reduced the gametocyte carrier rate from 37% to 6% and the mean gametocyte density from 80 to 1.4 per mm3 of blood. Chloroquine and amodiaquine were much less effective. Since SP has no gametocytocidal properties and the reduction in gametocytes coincided with clearance of asexual parasitemias, gametocytes were probably reduced subsequent to the cure of the asexual malaria infections. If used during the nontransmission season, SP might be an effective component of an integrated program for reducing malaria transmission in the Punjab and other areas where 4-aminoquinoline-resistant and SP-sensitive falciparum malaria exists.

The epidemiology of schistosomiasis in Egypt: methods, training, and quality control of clinical and ultrasound examinations.

Morbidity due to schistosomiasis was evaluated in a subpopulation of 14,000 of the randomized sample in the Epidemiology 1, 2, 3 Project. It was measured by using a standardized questionnaire for obtaining medical history and symptoms and by performing standardized physical and ultrasound examinations. Reported herein are descriptions of the methods and training and quality control efforts made to insure that the morbidity data was reliable and consistent when collected by 7 different teams in 9 different governorates.

The epidemiology of schistosomiasis in Egypt: Minya Governorate.

Risk factors, prevalence, and intensity of infection with Schistosoma sp. and prevalence and magnitude of morbidity caused by schistosomiasis was assessed in a stratified random sample of 16,433 subjects from 2,409 households in 33 rural communities in Minya Governorate, Egypt. The prevalence of S. haematobium ranged from 1.9% to 32.7% among the communities and averaged 8.9%. The average intensity of infection was a geometric mean egg count (GMEC) of 8.5 per 10 ml of urine and ranged from 1.6 to 30.9. Prevalence was maximum (18-20%) in those 10-20 years of age and higher in males than in females. Intensity of infection followed the same pattern. Infection with S. mansoni was present almost exclusively in a single village, confirming spread of this species up the Nile River and its focality in Minya. Risk factors for S. haematobium infection were an age from 11 to 20; male gender; males bathing in, women washing clothing or utensils in, and children swimming or playing in canals; and a history of, or treatment for, schistosomiasis. Recent history of burning micturition was associated with infection in children but not in adults, while a history of blood in urine correlated with S. haematobium infection in both age groups. Reagent strip-detected hematuria and proteinuria were highly associated, particularly in children, with S. haematobium infection. The presence of hepatomegaly or splenomegaly on physical examination was not associated with S. haematobium ova in the urine. Hepatomegaly, as measured by ultrasonography in the midclavicular line or the midsternal line, or ultrasonography-detected splenomegaly were not present more frequently in infected subjects than in uninfected subjects. Schistosoma ova were not detected more frequently in urine of subjects with ultrasonography-detected periportal fibrosis than in the urine from subjects without this finding. Ultrasonography-detected urinary bladder wall lesions were detected in only 6 (0.3%) subjects and obstructive uropathy was observed in 54 (2.7%) subjects. The absence of an association between prevalence of urinary tract morbidity and S. haematobium infections was surprising. Two possible explanations are 1) that repeated chemotherapy has reduced the prevalence of urinary tract morbidity and 2) that morbidity was not being detected by the ultrasonographic operators.

Parasite density and malaria morbidity in the Pakistani Punjab.

The relationship between quantitative Plasmodiumfalciparum or P. vivax parasitemia and clinical illness has not been defined in Pakistan or in other areas where malaria transmission is not highly endemic. Standardized questionnaires were given to and physical examinations and parasitologic tests were performed in 8,941 subjects seen in outpatient clinics in 4 villages for 13 consecutive months in the Punjab region of Pakistan. The results, based on multivariable analysis, showed that a clinical diagnosis of malaria, a history of fever, rigors, headache, myalgia, elevated temperature, and a palpable spleen among children were all strongly associated with the presence and density of P. falciparum or P. vivax malaria in a monotonic dose-response fashion. The malaria attributable fraction of a clinical diagnosis of malaria, and the same symptoms and signs also increased with increasing P. falciparum and, to a lesser extent, P. vivax, parasitemia. Unlike in sub-Saharan Africa, clinical illness due to malaria often occurs in the Punjab among adolescents and adults and in patients with parasite densities less than 1,000/microl. Clinical guidelines based upon parasitemia and symptomatology must be adjusted according to the intensity of transmission and be specific for each geographic area.

Tuberculous peritonitis in Egypt: the value of laparoscopy in diagnosis.

Abdominal laparoscopy was performed on 200 patients with undiagnosed ascites. It was unsuccessful in one patient with tuberculous peritonitis because of extensive adhesions. A presumptive diagnosis of tuberculous peritonitis based on clinical findings and peritoneal tubercles or adhesions visualized during laparoscopy was made in 90 of these patients. The diagnosis was confirmed in 88 by histopathology, bacteriology, or therapeutic response. Two of the 109 remaining patients who had other presumptive diagnoses made during laparoscopy were eventually confirmed to be cases of tuberculous peritonitis. Of 91 patients with tuberculous peritonitis included in this series, 79% were females, with the majority (79%) of them being of child-bearing age. Half had been ill for longer than one month. The most frequent complaints were abdominal pain, fever, anorexia, night sweats, abdominal swelling, and weight loss. Ascites, fever, wasting, pallor, and abdominal tenderness were common findings. Ultrasonography demonstrated ascites in all patients who underwent this procedure; 21% also had adhesions. Pleural effusion was present in 15% and pulmonary tuberculosis was detected in only two patients. Biopsy samples taken during laparoscopy showed that 60% had noncaseous granulomas and 33% had caseous granulomas. Mycobacterium tuberculosis was detected in 77%, with guinea pig inoculation having the highest sensitivity, followed by culture, and lastly by acid-fast smear. Mycobacterium tuberculosis was isolated more easily from biopsy samples than from ascitic fluid. Nine of 20 M. tuberculosis isolates that were identified as to species were M. bovis. Tuberculous peritonitis, a frequent cause of febrile ascites in Egyptian women, was easily diagnosed by histopathologic and bacteriologic studies of biopsy samples taken at laparoscopy. All patients responded rapidly to antituberculosis therapy.

Ultrasonographic changes of the liver in Schistosoma haematobium infection.

Abdominal ultrasonographic examination was performed in 61 hospitalized patients with chronic liver diseases and 253 school children from a village endemic for Schistosoma haematobium and were compared with 142 urban children without exposure to Schistosoma. The prevalence of ultrasound-detectable hepatomegaly and splenomegaly and the degree of periportal fibrosis was compared between those with and without S. haematobium infection. Among 13 patients with biopsy-proven schistosomal hepatic fibrosis, three with coarse changes secondary to S. mansoni infection showed grade III periportal fibrosis, while 10 patients with fine schistosomal hepatic fibrosis due to S. haematobium had borderline (two) or grade I (eight) changes. Ultrasound evidence of periportal fibrosis was not detected in patients with hepatic cirrhosis, chronic active hepatitis, or fatty infiltration. However, three of 14 patients with chronic persistent hepatitis had grade I periportal fibrosis and two had borderline changes. The frequency of ultrasound-detected hepatomegaly and splenomegaly was greater among rural S. haematobium-infected children (35.2% and 22.4%, respectively) than among noninfected rural (21.1% and 13.3%) and urban (16.9% and 4.9%) children. Also, the frequency of grade I periportal fibrosis was significantly greater (P less than 0.01) in S. haematobium-infected children (22.4%) than in noninfected rural (11.7%) and urban (0.7%) children. No patients with S. haematobium infections, either in the hospital or the village, had grade II or III periportal fibrosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Ultrasound-detected hepatic periportal thickening in patients with prolonged pyrexia.

Hepatic periportal thickening (HPT) detected by ultrasonography has been established as a reliable tool for measuring hepatic morbidity due to schistosomiasis. During ultrasonographic examination of patients with prolonged pyrexia, we frequently noticed minimal grades of HPT in patients without a history of schistosomiasis. This led to ultrasonographic studies of conditions other than schistosomiasis in which HPT may occur. Subjects included 460 patients with Schistosoma haematobium infection, 107 urban patients with prolonged pyrexia without previous exposure to schistosomiasis, and 288 healthy controls unexposed to schistosomiasis. Grade I HPT was more prevalent (P < 0.001) in patients with pyrexia (56.1%) than in those with S. haematobium (32.2%) and was more frequent (P < 0.001) in patients with S. haematobium than in controls (11.1%). Typhoid fever was the most common febrile illness causing HPT. Grade II lesions were rare in patients with pyrexia (2.8%) or schistosomiasis (0.9%). Grade III lesions were present in only one patient with S. haematobium. Mild grades of HPT can occur in infectious diseases other than schistosomiasis. Cellular infiltration in the portal tract from chronic infectious diseases can frequently give the ultrasonographic appearance of grade I HPT.

The impact of endemic schistosomiasis on acute viral hepatitis.

One hundred forty-four of 166 adults with acute viral hepatitis (AVH) admitted to an Egyptian fever hospital were followed for 12 months. The hepatitis B surface antigen (HBsAg) carrier rate in 95 with hepatitis B virus (HBV) hepatitis decreased from 53% at three months to 13% at 12 months. At 12 months, 22% of the male patients had persistent HBsAg compared with only 7% of the female patients. The HBsAg carrier rate was 25% at 12 months in those with schistosomiasis compared with 9% in those with only acute HBV infection. Splenomegaly persisted in those with palpable spleens at the initial examination and others developed splenomegaly. The prevalence of splenomegaly increased from 11% on admission to 20% at 12 months in those with only AVH, and from 40% to 69% in those with concomitant schistosomiasis. Patients with concomitant schistosomiasis had higher mean values for liver function test results and a greater proportion had abnormal liver function test results during hospitalization and follow-up than those with AVH only. Concomitant schistosomiasis increased the prevalence and prolonged splenomegaly and morbidity due to AVH. Both male sex and concomitant schistosomiasis prolonged the HBsAg carrier state. We propose that AVH frequently converts uncomplicated intestinal schistosomiasis to hepatosplenic schistosomiasis.

The epidemiology of schistosomiasis in Egypt: Menofia Governorate.

Health questionnaires and parasitologic examinations of urine and stool were performed upon a stratified random sample of 10,899 individuals from 1,537 households in 27 rural communities in Menofia Governorate in Egypt in 1992 to investigate the prevalence of, risk factors for, and changing pattern of infection with Schistosoma sp. in the governorate. A subset, every fifth household, or 1,480 subjects, had physical and ultrasound examinations to investigate prevalence of and risk factors for morbidity. The prevalence of S. mansoni ranged from 0.3% to 72.9% and averaged 28.5%. The geometric mean egg count was 81.3 eggs/gram of stool. Age-stratified prevalence and intensity of infection was 30-40% and 60-80 eggs/gram of stool from the age of 10 onward; males had higher infection rates and ova counts than females in all age groups > 10 years old. Schistosoma haematobium was rare, being consequential in only 1 community. Risk factors for S. mansoni infection were male gender; age > 10 years; living in smaller communities; exposures to canal water; history of or treatment for schistosomiasis or blood in the stool; detection of splenomegaly by either physical or ultrasound; and ultrasound-detected periportal fibrosis (PPF). The more severe grades of PPF were rarely (21 of 1,450 examinations) detected. Risk factors for morbidity, i.e., ultrasound-detected PPF, were similar to those for infection. Schistosoma mansoni has almost totally replaced S. haematobium in Menofia. The prevalence of S. mansoni in rural communities remains high and average intensities of infection are moderate. The association of morbidity with schistosomal infection was variable and is obviously markedly influenced by both the frequent use of antischistosomal chemotherapy in communities in Menofia and by the prevalence of complications from chronic viral hepatitis in the population: hepatomegaly did not correlate with infection; PPF and splenomegaly, however, were related to S. mansoni infection in both individuals and communities.