Malaria and typhoid fever are endemic diseases in Cameroon, with overlapping signs and symptoms. While the high prevalence of malaria is an established fact, it is only within the past 5 years that an unusually high number of illnesses have been diagnosed as malaria co-existing with typhoid fever. The Widal test is widely used as the sole laboratory test for the diagnosis of typhoid fever. To investigate the extent of the malaria and typhoid fever association, we used blood and stool cultures as additional diagnostic tests for typhoid fever. We report that, of 200 patients presenting with fever, 17.0% had concurrent malaria and typhoid fever (Salmonella typhi) based on bacteriological proven diagnosis as compared with 47.9% based on the Widal test. A higher proportion of patients (32.5%) had malaria coexisting with S. typhimurium when compared to S. paratyphi (2%) and S. typhi (P < 0.05). We conclude that the number of fever cases diagnosed as malaria co-existing with typhoid fever is overestimated.

Glycophorin, the major sialoglycoprotein of the erythrocyte membrane, was extracted from human erythrocyte ghosts by the lithium diiodosalicylate phenol (LIS) or chloroform-methanol (CM) methods. The products (LISgp and CMgp) were examined for their capacity to inhibit invasion of erythrocytes by Plasmodium falciparum in vitro. In the presence of either glycoprotein, parasitemia was significantly less than in control cultures, indicating competitive inhibition of attachment. Desialylation resulted in only partial loss of this inhibitory potency. Neither crystalline NANA nor the dialyzates of either hydrolyzed glycoprotein had any inhibitory effect. We conclude that the receptor for merozoites of P. falciparum probably resides in the protein portion of glycophorin, in which NANA plays a secondary role, possibly related to hydration of the cell surface. The parasite itself contains no detectable neuraminidase activity.

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Prior studies have linked retroviruses to various arthropathies and autoimmune diseases. Sjögren's syndrome (SS), a systemic autoimmune disease, is characterized by aggressive infiltration of lymphocytes into the salivary and lacrimal glands, resulting in destruction of the glands and dry mouth and eyes (sicca syndrome). The infiltrating lymphocytes in SS may become overtly malignant, and thus, the incidence of lymphoma is greatly increased in SS patients. A human intracisternal A-type retroviral particle type I (HIAP-I) has been isolated from persons with SS. HIAP-I shares a limited number of antigenic epitopes with human immunodeficiency virus (HIV), but is distinguishable from HIV by morphological, physical, and biochemical criteria. A substantial majority of patients with SS or systemic lupus erythematosus (SLE) have serum antibodies to the proteins of this human retrovirus. Fewer than 3% of the normal blood donor population have antibodies to any HIAP-associated proteins. A second type of a human intracisternal A-type retrovirus, HIAP-II, was detected in a subset of patients with idiopathic CD4 lymphocytopenia (ICL), an AIDS-like immunodeficiency disease. Most HIAP-II positive ICL patients were also antinuclear antibody positive. Reviewed here are additional studies from several laboratories suggesting that HIAP or related viruses may be involved in SLE and other autoimmune conditions. Additionally, results of comprehensive surveys of autoimmune patients to determine seroreactivity to HIAP, and other human retroviruses, including HIV and human T-lymphotropic virus type I, are reported.