Direct acridine orange fluorescence examination of blood slides compared to current techniques for malaria diagnosis.

The renewed interest in the use of fluorochromes for malaria diagnosis prompted us to evaluate the acridine orange fluorescence technique on blood slides, and to compare it with established techniques using thick and thin blood films and the QBC malaria test, using the Giemsa-stained thick film technique as our standard method for comparison. We compared 123 positively diagnosed cases and 120 negative cases. For primary samples (day 0), the sensitivity of the thin blood film fluorescence acridine orange technique (AO) was 96.4%, and its specificity was 95.1%. In cases of imported malaria, with a prevalence rate of 16.2%, the positive predictive value was 79.2% and the negative predictive value 99.3%. Sensitivity of AO was significantly higher than that of Giemsa-stained thin blood films for parasitaemias < 5000/microL. The potential of AO for species diagnosis of Plasmodium was 85.2%, using Giemsa-stained thin films as the reference technique. Where QBC imposes a cost limitation, especially in developing countries, despite its high performance, the AO diagnostic technique is a valuable alternative, because of its simplicity, almost negligible cost, and its diagnostic reliability. The method may also have potential value in the diagnosis of other microbiological diseases.

Malaria, cause of ahaptoglobinaemia in Africans.

The lack of serum haptoglobin in Africans has been investigated in the Congo, Central Africa, where HpO prevalence is about 30%. This study shows that it is possible to suppress ahaptoglobinaemia within a few weeks by antimalarial chemoprophylaxis, that it does not occur in protected individuals, that ahaptoglobinaemia reappears at its original incidence levels after interruption of chemoprophylaxis, and that some individuals are more susceptible in relation to Hp2 gene. Malaria is the only significant cause of ahaptoglobinaemia in subjects both with and without detectable parasitaemia. The possible mechanisms involved are discussed.

General considerations on endemic treponematosis in the rural Sahel region of Upper Volta.

A sero-immunological survey conducted by indirect immunofluorescence technique has made it possible to determine accurately the prevalence and distribution of treponematoses in the Sahel rural region of Upper Volta. The number of carriers of antitreponemal antibodies varies from one place to another, but is particularly high in a nomad community, where prevalence attains 84.2%. The magnitude of endemic foci can also be expressed in terms of maximal titer and geometric mean of antibody titers. The seropositive values increase as a function of age, but sex is not a significant factor as regards prevalence, which would appear to depend essentially on the way of life, habits and promiscuity.

Immunological evaluation of cell-mediated and humoral immunity in Thai patients with cerebral and non cerebral Plasmodium falciparum malaria: II. Evolution of serum levels of immunoglobulins, antimalarial antibodies, complement fractions and alpha interferon.

In Thai patients with Plasmodium falciparum malaria, IgG and IgM values were elevated, whereas IgA levels were within normal ranges. No association of Ig values with parasitaemia was noted. IFA-IgM antibody levels were lower in cerebral malaria (CM) than in the non cerebral malaria (NCM) group. IFA-IgG antibodies were present in all patients. The mean C3 and C4 values were similar among patients from the CM and NCM groups. Interferon like activity was detected in all CM and NCM patients, and no correlation was found with either antimalarial antibodies, complement or parasitaemia.

[Transfer of measles immunoglobulins and antibodies from mother to child in Africa and Europe]. / Transfert des immunoglobulines et des anticorps antirougeoleux de la mère à l'enfant en Afrique et en Europe.

In a series of 50 mother-child pairs from Paris the titers of measles antibodies in cord blood were 1.4 times higher that those measured in the mother's blood, but this ratio was only 0.92 in 116 African mother-child pairs from Libreville (Gabon). Similarly, the ratio of immunoglobulin G levels in cord blood to those of the mother's blood was higher in Paris (1.34) than in Libreville (0.88). This limitation in active transfer of total of specific immunoglobulins is due to their high levels usual in African mothers, and this is not without repercussions on the immune defence mechanisms of African newborns.

[Blood histamine levels in patients infected with the human immunodeficiency virus]. / Histaminémie des malades infectés par le virus de l'immunodéficience humaine.

Serum histamine levels are significantly lowered in patients with human immunodeficiency virus (HIV) infection. Treatment with zidovudine has no effect on histaminaemia, but HIV-positive patients with thrombocytopenic purpura who underwent splenectomy are known to have had a rise in serum histamine levels after the operation. This parameter might be used as prognostic factor in the evaluation of patients with HIV infection.

Ahaptoglobinemia in African populations and its relation to malaria endemicity.

A study of the relations between plasma haptoglobin levels and malaria endemicity was carried out on selected specimens collected in 1980-1985 during studies on malaria transmission in various populations of the Brazzaville region of the Republic of the Congo. The prevalence of ahaptoglobinemia in school-children is 2.2% in Moungali and 2.9% in Poto-Poto, two districts of Brazzaville where malaria transmission intensity is less than one infective mosquito bite per person per year and malaria prevalence in schoolchildren is less than 10%. In contrast, ahaptoglobinemia prevalence is 48% in schoolchildren from the village of Djoumouna, where malaria transmission intensity reaches 1,000 infective bites per person per year and malaria prevalence in schoolchildren is 94%. Intermediate values, between 11.1% and 23.4% are observed in schoolchildren from Talangaï, Massina, and Linzolo, districts or villages where malaria transmission intensity is between 20 and 250 infective bites per person per year and malaria prevalence in schoolchildren is between 66% and 81%. These findings indicate that ahaptoglobinemia prevalence is correlated with the level of malaria endemicity and provide additional support for the hypothesis that malaria is the main cause of ahaptoglobinemaia in African populations. The haptoglobin system may be of considerable interest in the investigation of the mechanisms of anemia in malaria.

A genetic study of two French Guiana Amerindian populations. II. Rare electrophoretic variants.

Two Amerindian populations of French Guiana were investigated for plasma proteins and red-cell enzymes. In the Wayampi tribe, rare variants were identified in 4 systems. The corresponding alleles are designated AK1 3 Wayampi, PGM1 (4/10) Wayampi, PGM2 6 Wayampi, and TfD. In the Emerillon tribe, a variant allele of PGM2, designated PGM2 6 Emerillon, was identified. For three of the systems, PGM1, PGM2, Tf, similar isozymes have been described in other Amerindian populations. These findings suggest that the corresponding alleles may have the same origin.

[Transplacental passage of toxoplasma antibodies. The difference between African and European mothers]. / Passage transplacentaire des anticorps toxoplasmiques. Différence entre la mère africaine et européenne.

The transplacental transfer of toxoplasmosis antibodies has been compared between european and african cord/mother ratios. A lack of transfer is statistically noticed among african cord-mother pairs. This transfer deficiency is highly significantly negative correlated with mother total IgG level.

[Endemic syphillis in Upper Volta. A peculiar aspect of the epidemiological profile]. / La syphilis endémique en Haute-Volta. Un aspect particulier du profil épidémiologique.

A seroimmunological survey was realised in Upper Volta using an indirect immunofluorescence technique. It showed that endemic syphilis also known as bejel is not exclusively encountered in Sahelian regions. So, in Kora village which is located in a savannah area prevalence was around 10.3%. The disease particularly affects males. Congenital syphilis is certainly exceptional for first cases of serological treponematosis were only detected after 5 years. Endemic syphilis distribution in microfocuses in the village area underlines that promiscuity acts as a contributing factor for contamination.