Ana Lúcia Coutinho Domingues

Cytokine Production in Acute versus Chronic Human Schistosomiasis Mansoni: The Cross-Regulatory Role of Interferon-γ and Interleukin-10 in the Responses of Peripheral Blood Mononuclear Cells and Splenocytes to Parasite Antigens

The contribution of interleukin (IL)-10 and interferon (IFN)-gamma to the regulation of type 1 and type 2 cytokine responses was investigated in Brazilians with different clinical forms of schistosomiasis mansoni. Cells from members of a family with acute intestinal schistosomiasis responded to schistosomal soluble egg antigen (SEA) or soluble adult worm antigen preparation (SWAP) with greater amounts of IFN-gamma than did cells from several patients with chronic intestinal schistosomiasis; IL-10 levels were similar. Neutralization of IL-10 had no effect on the SEA-specific IFN-gamma response in patients with acute infection, whereas SWAP-induced IFN-gamma was increased in both groups. Anti-IL-10 also up-regulated SEA-specific IFN-gamma protein and mRNA responses in most splenocyte cultures from hepatosplenic schistosomiasis patients but had no effect on antigen-specific IL-4 or IL-5 production. Neutralization of IFN-gamma resulted in a comparable increase in SWAP-specific IL-10 and IL-5, while IL-4 was not affected. These studies demonstrate that early disease in schistosomiasis is associated with a significant IFN-gamma response and that IL-10 contributes to the suppression of that response during both early and chronic infection.

Report of the Second Satellite Symposium on Ultrasound in Schistosomiasis

A group of experts on schistosomiasis and ultrasonography discussed the experiences and results obtained with the Niamey-Belo Horizonte Protocol on Ultrasonography in Schistosomiasis. A series of recommendations about qualitative and quantitative data obtained by ultrasound in studies performed in Africa and Brazil are presented. Immunological, genetic and epidemiological studies must rely on ultrasound for the identification of patients with periportal thickening/fibrosis.

An outbreak of acute schistosomiasis at Porto de Galinhas beach, Pernambuco, Brazil

We recently confirmed several cases of acute schistosomiasis in Porto de Galinhas beach, Northeast Brazil. A total of 662 patients were diagnosed by parasitological and clinical examinations. The infection likely occurred during the September 7 national holiday, when heavy rainfall flooded the Ipojuca River and people were infected when the water covered their yards. Families were continuously exposed to infection for a period of three weeks until the water had completely dried up. Previous investigation suggests that snail vectors were introduced as a result of landfill in marshy areas. The swamp-flooding of such areas facilitated the emergence of slums surrounded by snail breeding sites. Heavy rainfall caused open-air sewage ditches to overflow, allowing for infection of snails by Schistosoma mansoni. Thus, continuous floods were responsible for the spread of human infection. Clinical and laboratory results identified 62% of acute cases of S. mansoni. Complementary studies are being conducted to define the impact and epidemiological meaning of the acute schistosomiasis outbreak.

An ultrasonographic study of liver fibrosis in patients infected with Schistosoma mansoni in north-east Brazil

Between August 1988 and July 1990, 176 patients with Schistosoma mansoni infection attending the University Hospital, Recife, Brazil received a complete clinical examination including stool examination for intestinal parasites, liver function tests, and ultrasonography. The majority were also examined by upper digestive tract endoscopy. The clinical distribution of their disease was as follows: 26.7% intestinal, 13.6% hepato-intestinal, 53.4% compensated hepatosplenic and 6.3% decompensated hepatosplenic. Infection intensity was high, with a median of 360 eggs/g of faeces. Ultrasonography showed a good correlation between the degree of hepatic periportal fibrosis and the clinical stage of disease (P < 0.0001). Of the patients with the intestinal form of schistosomiasis, 12.8% had grade I fibrosis and the others had no fibrosis; 33.3% of patients with hepatointestinal schistosomiasis had grade I fibrosis, 8.3% had grade II fibrosis, and 58.4% had no fibrosis; all the patients with hepatosplenic disease had grade II or grade III fibrosis. The degree of liver fibrosis detected by ultrasonography correlated with the degree of oesophageal varices detected by endoscopy (P = 0.0001). The degree of oesophageal varices also correlated with the presence of haemorrhage (P < 0.0001). Ultrasonography is considered superior to liver biopsy, permitting a dynamic approach to the study of schistosomiasis morbidity with precise diagnosis and simple sequential follow-up of post-treatment results.

Factors involved in Schistosoma mansoni infection, in rural areas of northeast Brazil

Two contiguous villages in Tracunhaém county (State of Pernambuco), endemic for schistosomiasis, were studied: Itapinassu (138 inhabitants) and São Joaquim (91 inhabitants). Agriculture predominates in the former region while ceramics is the main activity in the latter. Although no statistical difference was found regarding prevalence, severe infection (> 400 epg) predominated in Itapinassu, probably related to the kind of occupation. No association was found between parasite burden and severity of disease, in spite of the high infection rates for Schistosoma mansoni in both communities (approx. 60%). Typical epidemiological features of schistosomiasis such as age-related prevalences and intensities of infection (high in children, low in adults) were also mutual characteristics. Nutritional status determined through anthropometric evaluation was carried out by measuring specific anthropometric indicators. A deficit of energy intake, as well as vitamin A and riboflavin deficiencies were detected. The prevalence of moderate or severe undernutrition in patients under 18 years old was 21.9% in Itapinassu and 24.1% in São Joaquim. In this group an association was found between prevalence of schistosomiasis and chronic undernutrition. Similarly, for patients over 18 year old the prevalence of undernutrition was higher than 20%. However, in this case no association between nutritional status and either prevalence of schistosomiasis or parasite burden could be detected. The two communities had not been treated for eight years.

Specific situations related to acute schistosomiasis in Pernambuco, Brazil

The present work reports on two epidemiological episodes resulting in acute schistosomiasis involving wealthy persons living in the State of Pernambuco, Brazil. The authors discuss the epidemiological, clinical and serologic characteristics of the acute infections and also the way in which the conditions for transmission occurred.

Prevalence of pulmonary hypertension in patients with schistosomal liver fibrosis.

Abstract Between the April and July of 2007, patients undergoing treatment for schistosomal liver fibrosis, at a university hospital in north–eastern Brazil, were examined by transthoracic Doppler echocardiography (TTE). The main aim was to determine the prevalence of pulmonary hypertension in the patients. The thorax of each patient who had such hypertension, as indicated by an estimated pulmonary arterial systolic pressure (PASP) in excess of 35 mmHg, was then investigated by contrast-enhanced multidetector-row computed tomography (MDCT). The 84 patients (53 women and 31 men) enrolled in the study had a mean (S.D.) age of 50.06 (12.25) years. Nine (10.7%, with a 95% confidence interval of 5.0%–19.4%) of the patients were found to have pulmonary hypertension, with PASP ranging from 40–126 mmHg, and a median (S.D.) PASP of 58.78 (28.01) mmHg. The contrast-enhanced thoracic MDCT indicated that most of the patients with pulmonary hypertension had a pulmonary artery trunk that was unusually wide (67%) and more than 1.1-fold wider than the ascending aorta (56%), dilatation of the main pulmonary arteries (100%), a segmental artery that, in diameter, was more than 1.1-fold larger than the adjacent bronchi (89%), tapering of the peripheral pulmonary arteries (78%), and cardiac enlargement (78%). No patient suffered pulmonary embolism as a result of the investigations. The prevalence of pulmonary hypertension in the patients with schistosomal liver fibrosis (10.7%) justifies the screening of such patients by TTE.

Hepatopulmonary syndrome in patients with Schistosoma mansoni periportal fibrosis

UNLABELLED Hepatopulmonary syndrome (HPS) is characterized by the presence of liver disease, arterial hypoxemia and intrapulmonary vascular dilatation (IPVD). IPVD includes diffused or localized dilated pulmonary capillaries and, less commonly, pleural and pulmonary arteriovenous communications. The aim of the present study was to investigate the occurrence of HPS in patients with Schistosoma mansoni periportal fibrosis in treatment at a university hospital in northeastern Brazil. PATIENTS AND METHODS Eighty-four patients were enrolled in the study between April and July 2007 and underwent arterial blood gas analysis. Patients with an alveolar-arterial oxygen gradient (DA-aO(2)) > or = 15 mmHg were submitted to contrast-enhanced transthoracic echocardiogram (CE-TTE) with saline microbubbles. The diagnostic criterion for HPS was DA-aO(2) > or = 15 mmHg associated to IPVD, as identified through CE-TTE. Patients with HPS underwent contrast-enhanced 16-channel multidetector-row computed tomography (MDCT) of the thorax. RESULTS Twenty-two patients (26.19%) had DA-aO(2) > or = 15 mmHg (mean value=20.86+/-7.91). CE-TTE was positive for IPVD in five of the 22 patients with DA-aO(2) > or = 15 mmHg and all these patients had hepatosplenic disease, revealing a 6% prevalence of HPS (CI: 1.96-13.35) in the overall population of 84 patients, with a 10.2% prevalence in the group with hepatosplenic disease. The following were the 16-channel MDCT findings in these five patients: dilated peripheral pulmonary vasculature (100%); ratio of segmental arterial diameter to adjacent bronchial diameter equal to or greater than 2:1 (100%); higher number of visible terminal vessel branches in lung dependent regions (40%); and micronodules associated with subpleural surface centrilobular vessels (40%). No patient had evidence of arteriovenous fistula. These findings reveal that HPS occurs (usually in a mild form) in patients with Schistosoma mansoni periportal fibrosis and portal hypertension seems to be an important factor related to the occurrence of HPS in such cases.

Cytokine profile associated with chronic and acute human schistosomiasis mansoni.

The production and regulation of interleukin (IL) IL-13, IL-4 and interferon-gamma (IFN-gamma) was evaluated in 43 schistosomiasis patients with different clinical forms. Whole-blood cultures cytokine production in response to soluble egg antigen (SEA), soluble worm adult preparation (SWAP), mitogens, neutralizing antibodies or recombinant IL-13 were measured by ELISA. After SWAP stimulation, chronic patients, particularly hepatointestinals, produced higher levels of IL-4 in comparison with acute patients, suggesting the presence of a type 2 cytokine profile in these patients. Following SEA and SWAP stimulation, hepatosplenic (HS) patients showed increased levels of IFN-gamma when compared with acute patients, indicating that HS disease in humans is associated with a type 1 cytokine response. The mechanisms of immune regulation are apparently different between the clinical stages of the disease, some of which are antigen-specific.

The endemisation of schistosomiasis in Porto de Galinhas, Pernambuco, Brazil, 10 years after the first epidemic outbreak

In 2000, after heavy rains and floods in Porto de Galinhas, Pernambuco, Brazil, an outbreak of schistosomiasis was recorded, of which 62.2% (412 cases) were of the acute clinical form. Between 2001-2009, occasional findings of Biomphalaria snails parasitised by Schistosoma mansoni indicated that disease transmission was still occurring. This motivated a new epidemiological survey between August-December 2010 to provide an update of the occurrence of this health hazard and to investigate the process of disease endemisation at this locality. This survey gathered parasitological, clinical and malacological data. The results of this survey, compared with data from the year 2000 survey, showed the following: (i) over these 10 years, there were declines in the total percentage of cases and the percentage of acute forms, (ii) the acute clinical form now represents 23.3% in contrast with the 62.2% detected in 2000 and (iii) the current prevalence of schistosomiasis is 15.7%, while in 2000 32.1% of the individuals were diagnosed as parasitised. Today, the chronic clinical form represents 76.7% of the total number of cases diagnosed, thus showing that over the 10-year period the occurrences of clinical forms became inverted. These findings, together with visual observation of insalubrious environmental conditions, indicate that schistosomiasis has become endemic in Porto de Galinhas.