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People living with HIV (PLHIV) frequently travel, including to the tropics, with a variable risk of infection by one of the species of Plasmodium, the hemoprotozoan parasite responsible for malaria. The HIV-malaria co-infection increases the risk of severe malaria, in proportion to the degree of immunosuppression. Protective measures against mosquito bites and antimalarial drug prophylaxis are recommended for PLHIV travelling to malaria highly endemic areas. PLHIV, as compared to the general population, are less likely to attend a pre-travel consultation prior to departure. Among returning travelers with malaria, early diagnosis and artemisinin-based treatments are the main determinants of successful treatment outcome.

Malaria, which was eliminated first from Metropolitan France (mainland and Corsica), then in the French West Indies and the Reunion Island during the 20(th) century, remains endemic in two French territories: French Guiana and the Indian Ocean Mayotte island. Despite differences in the dominating plasmodial species and epidemiological patterns, these two territories have achieved marked quantitative improvements (in the reported number of cases and severe cases) thanks to efforts undertaken over the past decade. The situation, however, remains a concern from a qualitative standpoint with the emergence of resistance to antimalarial drugs and logistical and administrative issues which hinder access to treatment. Although malaria was eradicated in Metropolitan France half a century ago, competent vectors remain present in part or all of these territories and can give rise to limited outbreaks., (Copyright © 2011 Elsevier Masson SAS. All rights reserved.)

Infection by Plasmodium, the causative agent of malaria, starts when the parasite, injected by a mosquito vector, reaches and invades the liver, where it transforms into a stage that is capable of infecting erythrocytes and that causes the symptoms and complications of the disease. This phase of the infection, called pre-erythrocytic stage, is the most elusive of the parasite's life cycle, yet it was identified more than fifty years ago as a primary target of vaccine strategies aimed at avoiding erythrocyte infection. Recently in vivo imaging in a rodent model revealed that the pre-erythrocytic phase is unexpectedly complex. In particular, it includes a component of lymphatic infection, thus altering our representation of how an immune response can be mounted against these parasite stages.

This article analyzes the results of a one-year entomological survey conducted near the Yalala rapids in the Inga region, Democratic Republic of Congo, prior to the implementation of Community-Directed Treatment with Ivermectin (CDTI). A vector control program had been undertaken from October 1969 to December 1980, 20 kilometers upstream from the study site. The results of the present study show that during 122 collection days, 5,824 females were captured, of which 3,899 were dissected; 2,001 (51.3%) were parous while 44 (2.2%) were infected while 4 (0.2%) were infective. The crude Annual Transmission Potential (ATP) was 65 infective larvae per man and per year at the river as against 12 in Yalala village located two kilometers from the rapids. The average biting rate was 5 flies/man/day during the dry season and 90 during the rainy season. The vector capacity of similium shows that the risk of transmission of Onchocerca volvulus to the human population was not only reduced in time (2-3 months), but was also negligible all year round.

Despite the relatively high frequency of imported malaria in metropolitan France, the transmission of malaria by transfusion is exceptional. The screening of donations to determine those at risk is performed by an interview, and by the testing of serology for defined groups of donors. However, the exclusion of a candidate 'at risk' as a blood donor, by a pre-donation interview, is not completely mastered and the discrimination by biological examination lacks sensitivity, as much for methodological reasons as for reasons linked to the complex parasitic pathogenic agent (Plasmodium ssp.), as for the specific host defence system. The risk of introducing an unsafe-potentially dangerous (transfusion-transmitted malaria is often lethal)-element into the transfusional circuit is not completely covered. Is serology testing the most adequate test to avoid the risk of infected donations, in particular by Plasmodium falciparum; what are the alternatives and what will be the eventual added-costs of the biological qualification of such donations? The transfusional risk linked to Plasmodium seems, however, to be reduced to a minimum, concerning the circulation of plasma, which could represent an alternative for donors at real risk (rare) and those with a supposed risk (relatively numerous).

An epidemiological study on malaria was undertaken between July 1995 and July 1996 in two villages (Zaïpobly and Gahably) and their encampments (Kouassikro, Hamanikro and Konankro), in the south-western forest area of Côte d'Ivoire (region of Taï). The parasitological scheme comprised a total of 2023 tests performed on children aged from 0 to 14 years. The species found were Plasmodium falciparum, P. malariae and P. ovale with a proportion of 84%, 14% and 2% respectively. The global parasite prevalence of all Plasmodium species was 85% and malaria was holoendemic. The average parasitic density decreased progressively as the age increased, in contrast to the plasmodic index which did not vary. All the malarial indexes were similar in the villages and their encampments. Only overall fever prevalence was permanent and in all age groups it was higher in the encampments than in the villages. The entomological findings showed that transmission was permanent and intense throughout the year, with a recrudescence during the rainy season. Transmission was attributed to Anopheles gambiae s.l. in 85% of the cases whereas An. funestus played a secondary role. The average sporozoïtic index was 7.6% and varied between 1.1% and 16.7%. The entomological inoculation rate was of 400 infected bites per person-year for An. gambiae s.l. In such conditions of intense transmission, acquisition of premunition starts at a very early age. This assertion is verified by the average parasite density and the frequency of high parasitic densities which were at their maximum between 1 and 4 years of age and decreased thereafter as the age increased. The paludometric and entomologic indexes obtained are the most elevated ever to have been observed in Côte d'Ivoire, as a result of considerable ecological changes linked to the deterioration of the forest environment over the past 30 years. This deterioration has probably been caused by demographic pressure resulting from internal and foreign immigration to the Taï region and more especially by the influx of Liberian refugees.

Nowadays, malaria control is planned according to the epidemiological context. Various aspects of malaria have been described in sub-Saharan Africa. We report here entomological data from the coastal area of Benin, West Africa, which has many lakes and lagoons. We carried out a longitudinal study in which we investigated the dynamics of populations of malaria vectors in various zones, the frequency of inoculation in these zones, the infestation rate of the Anopheles gambiae mosquitoes collected, the effect of urbanization on malaria transmission, the effects of inundation and of salinity at mosquito breeding sites. A total of 3, 342 identifications were made on a chromosomal basis. Two species of the Anopheles gambiae complex were detected in the coastal and lagoon areas of Benin: An. melas and An. gambiae ss. The density of the populations of these species was highly dependent on the level of urbanization. In traditional villages on the lagoons (such as Agbalilamè, Djegbadji and Kétonou), the density of An. melas (86. 2%) was much higher than that in more urbanized areas (such as Ladji and Abomey-Calavi) (4.9%). We checked for chromosome polymorphism. We detected a 2Rn1 inversion in An. melas, similar to the 2Rn inversion found in mosquitoes in Gambia and Guinea-Bissau. The frequency of the n1 inversion and the density of An. melas populations were correlated and both seemed to depend on a single factor, salinity. The epidemiological situation with respect to malaria was very heterogeneous in the lagoon area of Benin. In the city of Cotonou, transmission was seasonal, sporozoite indices and the frequency of inoculation were high, in contrast to what would normally be expected in an urban area. In communities built on the beach, the level of transmission was markedly lower: about 5 infected bites per person per year versus 29 infected bites per person in the center of the city. In the traditional fishing villages, a paradoxical situation was observed in which the mosquitoes were very aggressive towards humans (4,502 bites per person per year) but the frequency of transmission was low (d = 0. 27%, CS+ = 0.57%). This was largely due to the high density in this area of An. melas, a poor malaria vector. If traditional villages become more urbanized, more freshwater breeding sites are created and the An. gambiae population increases, leading to an increase in malaria transmission. This is the reason for the higher level of malaria transmission at Ladji and Abomey-Calavi (h = 47 infected bites per person per year) than at Agbailamè, Djegbadji and Kétonou (h = 12.1 infected bites per person per year)

A longitudinal study on malaria vectors and transmission was carried out in a forest-savannah transitional area in Cameroon. Indoor all night mosquito collections on human bait were performed during one year in two villages: Nditam and Ngoume. Nditam was located in a secondary forest block surrounded by savannah, while Ngoume was situated in an ancient forest block. The results showed that at Nditam, only one anopheline species was collected, that was Anopheles gambiae s.l.. The average daily biting rate was 2.4 bites per man per night. The sporozoitic index of An. gambiae was 9.4%. The entomological inoculation rate was therefore estimated at 0.225 infective bite per man per night that is to say 82 infective bites per man per year. Malaria transmission was low during the year, but an important increase was observed in September, when the rainfall was at its peak. At Ngoume, no Anopheles mosquito was collected. Therefore, malaria transmission was not observed in that village.

From 1987 to 1993, a survey on the feeding behavior of Glossina fuscipes fuscipes was conducted in the Central African Republic. A total of 556 blood-meal samples was analyzed by ELISA. According to the results, the number of blood meals from cattle was rather low (12% on average). During the rainy season, this number increased significantly and varied according to the sampling area. Along the riverine forests, this amounted to 5%, while blood meals from wild ruminants amounted to 87%. In the neighborhood of watering-places, the number of cattle blood meals reached 9-22%. Reptiles were found to be important hosts (17-35%). In all cases, man presented a non-negligible host (4-14%), similar to suidae (2-19%). The authors discuss the relevance of these results to risk of trypanosomes transmission.