[The progress of malaria in sahelian eastern Niger. An ecological disaster zone]. / Evolution du paludisme dans l'est sahélien du Niger. Une zone écologiquement sinistrée.

The south eastern part of the Republic of Niger was ecologically damaged by the dryness since 1971. Rainfall decreased by 30 to 40% as compared to 1961-70 and lake Chad retreated 100 km to the south. Now it does not reach any more the Republic of Niger. Malaria studies have been carried out in urban and suburban places in Zinder and in the Diffa area at the extreme east. In Zinder parasitic indexes (PI) after the rainy season were around 30% to 10% according to the situation of the corner in respect with surface waters during the rains. In dry season the index fell to 3%. In Diffa in a part of the city at high risk because lining the Komadougou river, PI was only 6.7% in October after the rains. Before 1970 PI recorded in Niamey were up to 50%. In Diffa area they were of 49% in N'Guigmi and 32% in Bosso, ecologically similar to Diffa. Obviously there was a sharp decrease of malaria which could be due to the disappearance of An. funestus after 1970. It was one of the main malaria vectors. Its larvae were developing in pools remaining after the rains with heavy standing vegetation. These breeding sites have been destroyed by both dryness and human activities. Now the area has became hypoendemic and is suitable for epidemic because population has not much immunity. A surveillance system for epidemic control should be settle.

[Eco-epidemiology of malaria in Niamey and in the river valley, the Republic of Niger, 1992-1995]. / Eco-épidémiologie du paludisme à Niamey et dans la vallée du fleuve, République du Niger, 1992-1995.

The Niger valley is an original ecosystem in the Sahelian belt. For more than 25 years it has been affected by dryness and rainfall decreased by more than 30% as compared to the period 1950-1960. Moreover the demography has sharply increased and the capital town Niamey grew by 10% a year. The Niger valley including Niamey has about 1 million inhabitants. Three sites have been selected to study the status of malaria and its evolution for the last 30 years: Niamey, Karma 40 km on the N.W. on the river and the nearby fossil valley of Fatay-Karma. In the sixties the malaria vectors were An. gambiae, An. arabiensis et An. funestus. The last species was no more harvested after 1970 because its breeding places have been destroyed on the combined action of dryness and human activities. In Niamey, parasite index was very low in the dry season but grew by 5 to 10 times during the rainy season to reach 50% in certain corners. The highest plasmodic index (PI) were recorded along the river banks where vectors are found all the year long. It decreases in the central part of the city and becomes very low in some peripheral suburban settlements. This situation is quite different of most of the cities of the area where prevalence decrease from outskirts to city centre. The serology confirms these points. In Karma, along the Niger and despite a perennial transmission, the PI removes low as well as the malaria antibodies, probably because of the self use of antimalarial drugs by the population. In Fatay-Karma the PI of 23.9% after the rainy season drops to 6% in the dry one. In data prior to 1970 the PI was over 60%, reaching 89% in young children of Niamey suburbs. Obviously it has strongly decreased. It is very likely that this is due partly to the disappearance of An. funestus after the drought.

[Malaria knowledge and practice. Medical study in Songhay-Zarma (Niger)]. / Connaissances et pratiques face au paludisme. Enquête médicale en pays Songhay-Zarma (Niger)

Two randomized studies were performed in 1992 and 1994 in the Niger river valley where malaria transmission is thought to be permanent and is reinforced during the rainy season. The sample covered 114 families either in Niamey, the capital of Niger, or in Karma, a rural village 20 km to the west, and its surroundings. The questionnaire contained closed and open questions on the perception of malaria causes, treatment and prevention, including the use of mosquito bed nets. Most of the 114 families studied were monogamic with an average of 4 children per father. The most frequent occupation was agricultural farming (millet and rice) for the sedentary part of this population. During the rainy season, some moved to farms in the neighbouring valley of Taksaba. During the wet season, others migrated to the West African coast. The houses were traditional, being straw huts or made from banco; all the openings were small the the rooms were dark and poorly ventilated. These features constituted good conditions for malaria vectors. Domestic animals, such as goats, sheep, cows and sometimes donkeys, were very frequent in the courtyards. However, there was never any stagnant water in the courtyards or around the water pumps because of the intense sunshine. Drinking water was carried on the head from the public foot pumps or the river and stored in earth calabashes closed by a plate. In the Songhay-Zarma language, Hémar Izé is a symptomatic complex which corresponds closely to a clinical case of malaria. The main sign of this complex is fever known as konni (hot body). But this word is also used as the general name for all diseases with fever. Associated symptoms, well known by the community members, included vomiting, headache and diarrhoea. Hémar Izé was considered to be the most frequent cause of morbidity and the most severe disease, more significant than any other fever or diarrhoea. As perceived by the community members, the leading cause of malaria was described to be mosquitos (44.7%), followed by the rainy season, God, and less commonly, dirtiness, parasites, or the sun. The majority of cases were diagnosed by the parents, and were self-treated at home either with medicinal plant infusions or oral drugs. The self-treatment was not common, because Nivaquine was the only medication known by the people and was often unavailable. It is necessary to manage a regular drug supply with a public awareness campaign about dosage for self-treatment of malaria. Also, the public needs to be informed about any new policies of supplying essential drugs under generic names. Despite some confusion, the people generally believed that mosquitos were responsible for the disease. Thus, the use of mosquito netting over the beds was justified and widespread throughout the population. The traditional practice could be improved upon with an impregnated net even if the comprehension about the causes of the disease remains limited.