Developing appropriate strategies for EPI: a case study from Mozambique

In 1985 a ‘pulse immunization’ project was begunin southern Mozambique, to overcome the difficulties of deliveringimmunization services in rural areas. The project was closelymonitored in order to determine whether this strategy wouldbe appropriate on a national level. Major inputs were in trainingof both health workers and volunteers, and the development ofa system for communications and defaulter tracing via Mozambique'snetwork of grassroots organizations. By 1987 the project hadachieved 60% coverage of fully immunized children in safe ruralareas of the province, having reduced dropout rates betweenfirst and third doses of DPT/OPV from 49% to 11%. This paperdescribes the process of project development through situationanalysis, project design, implementation, monitoring and evaluation.Conclusions are drawn which may be relevant to other programmesin their attempts to accelerate immunization coverage in a sustainableway.     

Elimination of a primary schistosome infection from rats coincides with elevated IgE titres and mast cell degranulation

Schistosomes are eliminated from laboratory rats around 28 days post-infection, whilst they are still resident within the hepatic portal distributaries of the liver. We have previously shown that their presence in this location is accompanied by an intense mastocytosis. We have investigated the potential relationships between IgE responses, the allergenicity of schistosome antigens, mast cell responsiveness, and worm elimination. Total and specific IgE were measured using an ELISA and a functional assay based on ³H serotonin release from activated rat basophilic leukemia cells (RBL-SRA), respectively. Both assays revealed that infected rats produced elevated IgE titres relative to naive animals. At days 28 and 35, mixed-sex infections stimulated a higher total IgE than male-only infections. IgE was affinity purified from rat infection serum and used to probe a fractionated soluble worm antigen preparation (SWAP) by Western blotting. Two allergenic products were detected of M _r 67 and 36–38 kDa, the former having the same molecular weight as a previously identified secretory protein. IgE from mixed-sex schistosome infections bound strongly to the 36–38 kDa molecule, compared to the relatively weak binding exhibited by IgE from male-only infection serum. Since eggs were not recovered from the infected rats, this reactivity was attributed to the greater release of allergens from female worms. Results from the RBL-SRA showed that female SWAP was a more effective trigger of mast cell degranulation in vitro , for equal amounts of protein. This enhanced allergenicity was ascribed to the relative abundance of carbohydrate moieties. Our results support a role for IgE, and mast cell degranulation in the elimination of a primary schistosome burden from rats.     

Ficoll Flotation for the Separation of Blood Leukocyte Types

A method for the separation of leukocytes from peripheral blood, using flotation over Ficoll, is described. The method is amenable to considerable variation, and the leukocytes isolated show good preservation of their morphologicintegrity, are motile and capable of phagocytosis.

Submitted on May 3, 1967 Accepted on July 6, 1967