The effect of climatic factors on the number of malaria cases in an inland and a coastal setting from 2011 to 2017 in the equatorial rain forest of Cameroon

Raymond Babila Nyasa; Fuanyi Awatboh; Tebit Emmanuel Kwenti; Vincent P K Titanji; Ndip Lucy M Ayamba

doi:10.1186/s12879-022-07445-9

The effect of climatic factors on the number of malaria cases in an inland and a coastal setting from 2011 to 2017 in the equatorial rain forest of Cameroon

BMC Infect Dis. 2022 May 13;22(1):461. doi: 10.1186/s12879-022-07445-9.

Authors

Raymond Babila Nyasa^{1

2}, Fuanyi Awatboh³, Tebit Emmanuel Kwenti⁴, Vincent P K Titanji^{5

6}, Ndip Lucy M Ayamba^{3

7}

Affiliations

¹ Department of Microbiology and Parasitology, University of Buea, P. O. Box 63, Buea, Cameroon. nyasab@yahoo.co.uk.
² Biotechnology Unit, Faculty of Science, University of Buea, P.O. Box 63, Buea, South West Region, Cameroon. nyasab@yahoo.co.uk.
³ Department of Microbiology and Parasitology, University of Buea, P. O. Box 63, Buea, Cameroon.
⁴ Department of Medical Laboratory Sciences, Faculty of Health Science, University of Buea, P.O. Box 63, Buea, South West Region, Cameroon.
⁵ Biotechnology Unit, Faculty of Science, University of Buea, P.O. Box 63, Buea, South West Region, Cameroon.
⁶ Cameroon Christian University, P.O. Box 5, Bali, North West Region, Cameroon.
⁷ Laboratory for Emerging Infectious Diseases, University of Buea, P.O.Box 63, Buea, South West Region, Cameroon.

Abstract

Background: Weather fluctuation affects the incidence of malaria through a network of causuative pathays. Globally, human activities have ultered weather conditions over time, and consequently the number of malaria cases. This study aimed at determining the influence of humidity, temperature and rainfall on malaria incidence in an inland (Muyuka) and a coastal (Tiko) settings for a period of seven years (2011-2017) as well as predict the number of malaria cases two years after (2018 and 2019).

Methods: Malaria data for Muyuka Health District (MHD) and Tiko Health District (THD) were obtained from the Regional Delegation of Public Health and Tiko District Health service respectively. Climate data for MHD was obtained from the Regional Delegation of Transport while that of THD was gotten from Cameroon Development Coorporation. Spearman rank correlation was used to investigate the relationship between number of malaria cases and the weather variables and the simple seasonal model was used to forecast the number of malaria cases for 2018 and 2019.

Results: The mean monthly rainfall, temperature and relative humidity for MHD were 200.38 mm, 27.05⁰C, 82.35% and THD were 207.36 mm, 27.57 °C and 84.32% respectively, with a total number of malaria cases of 56,745 and 40,160. In MHD, mean yearly humidity strongly correlated negatively with number of malaria cases (r = - 0.811, p = 0.027) but in THD, a moderate negative yearly correlation was observed (r = - 0.595, p = 0.159). In THD, the mean seasonal temperature moderately correlated (r = 0.599, p = 0.024) positively with the number of malaria cases, whereas MHD had a very weak negative correlation (r = - 0.174, p = 0.551). Likewise mean seasonal rainfall in THD moderately correlated (r = - 0.559, p = 0.038) negatively with malaria cases, contrary to MHD which showed a very weak positive correlation (r = 0.425, p = 0.130). The simple seasonal model predicted 6,842 malaria cases in Muyuka, for 2018 and same number for 2019, while 3167 cases were observed in 2018 and 2848 in 2019. Also 6,738 cases of malaria were predicted for MHD in 2018 likewise 2019, but 7327 cases were observed in 2018 and 21,735 cases in 2019.

Conclusion: Humidity is the principal climatic variable that negatively influences malaria cases in MHD, while higher seasonal temperatures and lower seasonal rain fall significantly increase malaria cases in THD.

Keywords: Cameroon; Climate; Humidity; Malaria; Muyuka; Rainfall; Temperature; Titko.

MeSH terms

Cameroon / epidemiology
Climate*
Humans
Humidity
Incidence
Malaria* / epidemiology
Rainforest
Seasons
Temperature