Disease Schistosomiasis Research Articles

Past explosion and future threat: Exacerbation of red water disease (Schistosomiasis haematobium) in the Upper Region of Ghana

Past explosion and future threat: Exacerbation of red water disease (Schistosomiasis haematobium) in the Upper Region of Ghana

The effect of external infection on the endemic properties of schistosomiasis

We consider the effect of external infection on the endemic properties of a model for the transmission of the parasitic disease schistosomiasis. Particular attention is given to the qualitative changes in breakpoint and threshold results caused by the inclusion of external infection. The consequences of these changes on the control of the disease are also discussed.

Hepatitis-B virus determinants in patients with liver disease in Malawi

Sera from 185 patients admitted to hospital in Malawi with acute and chronic liver disease were tested for the following serological markers of hepatitis-B infection (HBV): hepatitis-B surface antigen (HBsAg) and its antibody (anti-HBs), HBe antigen (HBeAg) and its antibody (anti-HBe), and antibody to hepatitis-B core antigen (anti-HBc). Control groups consisted of patients without liver disease, students and blood donors. HBsAg was detected in 73%, 54·8% and 64% of patients with acute hepatitis, cirrhosis and hepatoma, respectively. 16% of patients with tropical splenomegaly syndrome (TSS) and 14·6% of patients with schistosomiasis, 9·5% of patients without liver disease, 1·4% of students and 7·6% of blood donors were HBsAg positive. Unexpectedly, 72·3% of HBsAg-positive specimens appeared to carry both major antigenic determinants ( ady). HBeAg was detected in 15·8% and anti-HBe in 13·1% of patients with acute HBsAg-associated hepatitis, these determinants being detected less frequently than in sera from patients with HBsAg-associated hepatitis in the UK. HBeAg or anti-HBe were rarely detected in patients with hepatoma. With the exception of students and blood donors, over 80% of the Malawian study population had markers of current or previous HBV infection in their sera. Anti-HBc occurred most frequently in patients with hepatitis, cirrhosis and hepatoma, their geometric mean titres (GMTs) being 67·6, 160·1 and 211, respectively. The GMTs of patients with TSS, schistosomiasis and non-hepatic disease were 2·0, 4·6 and 2·3, respectively.

Immunoregulation in Chronic Infectious Disease: Schistosomiasis as a Model

This review summarizes the current evidence that both the induction and amelioration of disease in hepatosplenic schistosomiasis are immunologically mediated. We hypothesize that the extent of disease depends on the balance between activation of immunologic disease processes and immunologic suppression of disease processes. In mice the major disease-producing process is granuloma formation, a cell-mediated hypersensitivity reaction to parasite egg antigens. There appear to be multiple possible pathways for the natural suppression of this hypersensitivity. Recent work on murine schistosomiasis in our own and other laboratories has detected 3 immunoregulatory systems and has developed tools to explore each of them. 1. Results from serum transfer experiments suggest that antibody-mediated immunologic blockade plays a role in modulating granuloma formation. Accurate radioimmunoassays, developed for the quantification of antibody to the major granuloma-producing antigens, may be useful in the elucidation of the mechanism of blockade. 2. Cell transfer experiments have demonstrated that suppressor T cells can inhibit the cell-mediated immune hypersensitivity reaction to schistosome eggs. Lymphokine assays, measuring specific suppressor cells may enable us to monitor this activity in man. 3. Mitogen-induced lymphocyte DNA synthesis is suppressed in chronic schistosomiasis. With this system we can examine nonspecific schistosome-induced suppressor cells from persons with schistosomiasis.

Modulation of Immunopathology and Disease in Schistosomiasis

Modulation of Immunopathology and Disease in Schistosomiasis

Calorie and protein malnutrition in chronic murine schistosomiasis mansoni: effect on the parasite and the host.

The effects of diets containing 8% and 4% protein and of 50% calorie-deficient diets on the host, the parasite, and the parameters of disease in chronic hepatosplenic schistosomiasis were studied in mice that were infected for 20 weeks with Schistosoma mansoni. Controls consisted of uninfected mice of the same size and age maintained on a balanced 20% protein diet. Each of four corresponding dietary groups of infected and uninfected animals was fed on its assigned diet from the 20th to the 24th week of infection. Between the 24th and the 28th week of infection, all groups were nutritionally repleted by being returned to the standard control diet. Changes in body weight and deaths were recorded throughout the experiment (20-28 weeks). Parasite and host responses were measured at 24 weeks and again at 28 weeks. Severe protein and calorie deficiencies were associated with diminished egg output, an effect that appeared to be residual in the most severely malnourished animals for some time after malnutrition has been corrected. In general, the parameters of hepatosplenic disease were less severe in the more severely malnourished animals; 50% calorie deficiency was the cause of greater amelioration than marked protein depletion. During the period of malnutrition the mortality rate in mice given the 4% protein diet was not significantly different from that in controls (approximately 30%), while that in the calorie-restricted animals was only 9%.

Predation of schistosomiasis vector snails by Ostracoda (Crustacea).

An ostracod species of Cypretta is an effective predator in laboratory experiments on 1- to 3-day-old Biomphalaria glabrata, a vector snail of the blood fluke that causes the tropical and subtropical disease schistosomiasis.

Clinical aspects of endomyocardial fibrosis in Bahia, Brazil

The clinical and laboratory findings of 12 patients from Bahia, Brazil, with endomyocardial fibrosis are presented. All the patients were from the poor socioeconomic group. Eight patients who died had necropsy confirmation. The disease may present in an acute and chronic form. The clinical picture of venous hypertension, refractory ascites, and peripheral edema was common to all patients at some stage. Chronic pericardial effusion was present in three cases. In 9 patients, the low QRS voltage in V 1 contrasted with the normal voltage of V 2. The chest film of 11 patients showed prominent bulge of the right cardiac border. A restrictive pattern was present in the right atrial pressure curve of 4 patients, and in the right ventricular pressure curve of 2. The main angiocardiographic findings were pericardial effusion and an enlarged right atrium. The differential diagnosis in this area includes Chagas' myocarditis, rheumatic heart disease, and hepatic and pulmonary schistosomiasis. It is hoped that this clinical presentation will lead to increased recognition of the condition in its early stages.

Primary Pulmonary Hypertension

Morphologic and morphometric studies were carried out on pulmonary vessels in lung tissue from 156 patients, for whom a diagnosis of primary pulmonary hypertension had been made. This material was collected from 51 medical centers. Chronic pulmonary thromboembolism can be recognized by organizing thrombi, patchy intimal fibrosis, and intra-arterial septa. The media is only slightly thicker than normal; in 31 of the 156 cases the vascular lesions corresponded to this pattern. Other conditions such as chronic pulmonary venous hypertension, pulmonary veno-occlusive disease, sarcoidosis, chronic bronchitis, and pulmonary schistosomiasis could also be classified from the morphologic criteria. The largest group comprised 110 cases showing medial hypertrophy, laminar intimal fibrosis, and often fibrinoid necrosis, arteritis, and plexiform lesions. These alterations suggest that they were initiated by vasoconstriction. In children the sex ratio is equal; in adults there are almost four females to one male. In these patients with vasoconstrictive primary pulmonary hypertension, various stimuli are likely to bring about vasoconstriction in the presence of a pronounced pulmonary vascular hyperreactivity. A review of 602 cases from the literature is given.

An application of the Kermack-McKendrick theory to the epidemiology of schistosomiasis.

A mathematical representation of the epidemiology of schistosomiasis was developed from the classic Kermack-McKendrick model of an epidemic process involving an intermediate host. The Kermack-McKendrick equations, which are not generally solvable for two-stage diseases such as malaria, are shown to be solvable for the four-stage disease schistosomiasis. Consequently, it was deduced from this model that 1) there exists a threshold condition stating that the susceptible snail population must not exceed a certain number to ensure against an epidemic outbreak of schistosomiasis among human beings, 2) this number represents the break point if it is not exceeded by the total active snail population (susceptible plus infective snails) because, under these circumstances, the disease in the human population will decline to the point of extinction, 3) in the event of an epidemic outbreak among human beings, the process will converge to an endemic state that is precisely at the threshold, and 4) the outcome of the epidemic process is independent of any variation above the threshold in the susceptible snail population. Hence, control of the disease may be achieved by maintaining the snail population at or below a certain critical level. That is, if the density of susceptible snails is above the critical level, an epidemic will occur, if the density of snails (susceptible plus infective) is above the critical level but the number of susceptible snails is at or below it, the process will be stable (endemic state), and if the density of snails falls to or below the critical level, then decline in the disease will ensue.

Cardiovascular diseases in China

Patients with organic heart disease constitute about 5 per cent of all hospital admissions in China. The relative incidence is as follows: rheumatic heart disease, 35 to 50 per cent; hypertensive heart disease, 11 to 40 per cent; atherosclerotic heart disease, 7 to 16 per cent; chronic pulmonary disease, 6 to 10 per cent; syphilitic heart disease, 2 to 6 per cent; and congenital heart disease, 4 to 7 per cent. Other conditions involving the heart have been reported. These include pulmonary edema of high altitude, cardiac arrhythmias following antimony treatment for schistosomiasis and Kershan disease. The last is a disease caused either by fungi poisoning or a rodent-born virus which produces acute or chronic myocardial necrosis. Progress and development in research and cardiovascular surgery are discussed.

Bulletin of the Ophthalmological Society of Egypt.

This bulletin contains the papers read before the Ophthalmological Society of Egypt on March 22 and 23, 1935, at the Giza Memorial Ophthalmic Laboratory, with Dr. R. P. Wilson presiding. At this meeting Dr. Mahmoud Azmy El-Kattan was elected president of the society for the ensuing year. In his opening address Dr. Wilson remarked that it was singularly appropriate that the next (fifteenth) International Congress of Ophthalmology was to be held in Cairo, as Egypt is the home of the earliest civilization and learning. Thirty-six papers on varied subjects were read. Among other topics the following were considered: the ocular complications of endemic diseases (schistosomiasis, ancylostomiasis, ascariasis, leprosy, pellagra, typhoid fever and ocular myiasis), by Dr. El-Tobgy and Dr. Wilson; plastic operations for the restoration of the upper lid, by Dr. El-Tobgy ; extraction of cataract by the electrodiaphacic method of Lacarrere, by Dr. M. Khalil (this paper has