Adverse reactions from community directed treatment with ivermectin (CDTI ) for onchocerciasis and loiasis in Ondo State, Nigeria

Onchocerciasis is an endemic disease in Ondo state, Nigeria. Community directed distribution of ivermectin is currently on-going in some local government areas of the state. Randomly selected persons (2 331 males and 2 469 females) were interviewed using a modified rapid assessment procedure for Loa loa (RAPLOA) to assess community directed treatment with ivermectin. The retrospective study evaluated the coverage, impacts and adverse reactions to the drug treatment. A questionnaire was administered by house-to-house visit in six local government areas, implementing community directed treatment with ivermectin (CDTI) in this bioclimatic zone. A total of 2,398 respondents were reported to have participated in the treatment. The overall ivermectin coverage of 49.96% was recorded (range 0 - 52% in different communities). Adverse reactions from ivermectin administration were experienced in 38% of individuals. Diverse adverse reactions experienced included predominantly itching (18.50%); oedema, especially of the face and the limbs (8.2%); rashes (3.4%) and body weakness (2.4%). Expulsion of intestinal worms occurred in 0.96% of the respondents. The occurrence of adverse reactions in relation to age categories was statistically significant. Neither fatal nor severe adverse reactions were reported by respondents. Significantly, despite experienced adverse reactions, continued participation, acceptability and compliance to ivermectin treatment was expressed by the various communities. This attitude is in consonance with the African Programme for Onchocerciasis Control (APOC) objectives. Rev. Biol. Trop. 56 (4): 1635-1643. Epub 2008 December 12.

La oncocercosis es endémica en el estado Ondo, Nigeria. Se seleccionaron 4 800 personas al azar para evaluar con encuesta retrospectiva la cobertura, efectos y reacciones al tratamiento farmacológico con ivermectina administrado por la misma comunidad. La cobertura global de ivermectina fue 50 % con reacciones adversas en 38 % de los individuos. Estas fueron comezón picazón (18%), edema, especialmente de la cara y las extremidades (8%), erupciones cutáneas (3%) y debilidad (2%); dependieron de la edad y no hubo reacciones más graves. La expulsión de las lombrices intestinales se produjo en 96% de los encuestados. A pesar de las reacciones adversas, hubo continuidad, aceptación y cumplimiento del tratamiento con ivermectina, en consonancia con los objetivos del Programa Africano para el Control de Oncocercosis (APOC).

Behaviour and population dynamics of the major anopheline vectors in a malaria endemic area in southern Nigeria.

BACKGROUND & OBJECTIVES: Anopheline mosquitoes consist of a large number of species each of which differs from another in population, resting and feeding behaviour in relation to the prevailing conditions in the locality. A longitudinal study was carried out to investigate the population dynamics, resting and feeding behaviour of the major anopheline species found in a rain forest zone of Nigeria. METHODS: Mosquitoes resting and biting indoors were collected using WHO standard techniques and supplemented with outdoor-biting collections in the study areas between January and December 2004. Samples were sorted and identified microscopically for morphological features while molecular identification was carried out using polymerase chain reaction (PCR) techniques. RESULTS: PCR-based tests showed that both indoor and outdoor collections constitute three groups of Anopheles mosquitoes, An. gambiae s.l. Giles (68.6%), An. funestus Giles (30.7%) and An. moucheti Evans (0.7%). Of the 1342 female Anopheles mosquitoes collected indoors, 799 were caught resting and 543 were caught biting. The outdoor-biting population accounted for 28.8% of the total collections (n=1885). There was no significant difference (p > 0.05) in the biting activities (indoors and outdoors) of these species in four villages. However, An. arabiensis and An. moucheti were more exophagic with >60% of their biting occurring outdoors while An. gambiae and An. funestus were more endophagic with >55% of their biting occurring indoors. The human-vector contact with An. gambiae and An. funestus (indoors) was about 73.3 and 66.7%, respectively as against 27.7% in An. arabiensis and 25.3% in An. moucheti. This gave the corresponding man-biting rates (MBR) of 17.5 bites/man/night for An. gambiae, 14.6 bites/man/night for An. funestus, 6.7 bites/man/night for An. arabiensis and 4.3 bites/man/night for An. moucheti. Moreover, the number of An. gambiae and An. funestus caught resting indoors was significantly higher than the other two species (p < 0.05). The wet season collections showed thatAn. gambiae caught were more than 67% of the total catch while An. arabiensis was predominant in the dry season (chi2 = 75.44, df = 3, p < 0.01). INTERPRETATION & CONCLUSION: The present study highlights some aspects of the behaviour of anopheline mosquitoes in southern Nigeria which is an important component of epidemiological study of malaria. This information provides basis to the understanding of the role played by the identified anopheline species in malaria transmission and a baseline to formulate malaria control programme.