NiMet: Weather conditions in March, April could lead to high prevalence of malaria

In its 2024 seasonal climate prediction, the Nigerian Meteorological Agency (NiMet) outlined how climate information can be used to monitor, predict, and manage health risks.

Climatic conditions such as high temperatures, relative humidity and rainfall can influence the outbreak and transmission of some diseases. Malaria, cerebrospinal meningitis, and heat stress are common climate-related health challenges in Nigeria.

The World Malaria Report 2023 published by the World Health Organisation (WHO) found that in 2022, there were 249 million cases of malaria worldwide and Nigeria accounted for 27 percent of the cases and 38.5 percent of malaria deaths in children under 5 years.

Meningitis epidemics, on the other hand, are more common in sub-Saharan Africa and are associated with high temperatures and airborne dust. 

According to the Nigerian Centre for Disease Control (NCDC), Nigeria recorded 2,765 suspected and 303 confirmed cases of meningitis with 190 deaths across 140 LGAs in 30 states and the federal capital territory (FCT) in 2022/2023.

NiMet said its prediction of climatic conditions may be used in determining the likelihood of outbreak and severity of malaria and meningitis cases across the country.

MALARIA VIGILANCE FORECAST

The International Research Institute for Climate and Society (IRI) defines seasonal climatic suitability for malaria transmission as the chance of precipitation accumulation greater than 80 millimetres (mm), average temperature between 18°C and 32°C, and relative humidity greater than 60 percent.

The combined values of these climate variables at a given location or region are an indication of the lower limit for potential malaria transmission in the area. This implies that once these conditions are met, malaria cases are likely to occur.

The predicted rainfall, temperature and relative humidity are used in determining the degree of vigilance for malaria.

NiMet said the climatic conditions for January 2024 were conducive for mosquitoes to breed during the month. High malaria vigilance was advised in the coastal states such as Lagos, Ondo, Delta, Bayelsa, Rivers, Akwa Ibom, and Cross River, while moderate vigilance was prescribed in parts of Ogun, Imo, and Anambra states, and low vigilance was advised over the rest of the country.

For February, the agency said the climatic conditions in Lagos, Ondo, Delta, Bayelsa, Rivers, Akwa Ibom, and Cross River states had high prospects of malaria cases. Moderate malaria vigilance was advised in Ogun, Osun, Imo, Enugu, Ebonyi, Abia, and Anambra states while low vigilance was advised over the central and northern states because the predicted temperature, rainfall and relative humidity were not conducive for mosquitoes to breed.

NiMet said the weather conditions for March will favour the breeding of mosquitoes in the southern region of Nigeria and some parts of Benue. The agency said it is very likely that the prevalence of malaria will be high in those areas and therefore advised high vigilance.

Moderate malaria vigilance is recommended for Oyo, Ekiti, Anambra, Enugu, Ebonyi and parts of Kwara, Kogi and Benue states while low vigilance is advised in the north.

NiMet’s prediction for April suggests a high probability of the emergence of malaria cases in southern states and lower chances in the central states. For May, NiMet said with the northward progression of rainfall, the south and central states have high chances of malaria cases.

MENINGITIS VIGILANCE FORECAST

Mean air temperatures, relative humidity, and concentration of dust in the atmosphere are major risk factors for meningitis. However, meningitis outbreaks are unlikely to occur with any significant amount of rainfall.

NiMet said the climatic conditions for January suggested a high probability of meningitis cases in parts of Sokoto, Jigawa, Yobe, Bauchi, Gombe, and Borno states, and as such, high vigilance was advised.

Moderate vigilance was advised in Plateau, Nasarawa and Taraba states while slim prospects of meningitis cases are expected in the inland states of the south, and in Benue, Niger, Kwara states, and the FCT, hence low vigilance. The agency said the occurrence of meningitis is unlikely in the coastal areas.

For February, NiMet predicted northern states to be under high and moderate meningitis vigilances. The agency recommended low vigilance in FCT, Benue, Kwara, Kogi, Oyo, Osun, Ekiti, Enugu, Parts of Ogun, Ondo, Edo, Anambra, Ebonyi, and Cross River states, adding that the emergence of meningitis is unlikely in the remaining parts of the south.

NiMet recommended high vigilance for Sokoto, Katsina, Zamfara, Kano, Jigawa, Bauchi, Yobe and Borno states, based on the predicted climatic conditions in March. In parts of Kebbi, Niger, Zamfara, Kaduna, Taraba, Adamawa, Plateau, Benue, Kwara, Kogi, Nasarawa states and the FCT, moderate to low vigilance is advised. The agency said it is improbable that meningitis will spread through the southern states in March.

The agency said the rainfall, temperature, relative humidity and dust concentration in the atmosphere suggest a high probability of meningitis in parts of Sokoto, Zamfara, Katsina, Jigawa, Yobe and Borno states in April. High meningitis vigilance is therefore recommended for those states.

Moderate meningitis vigilance is advised over parts of Gombe, Kebbi, Adamawa, Kano, Kaduna and Kebbi states, while low vigilance over Niger, Kaduna, Adamawa, Taraba, and Plateau states.

NiMet said the climatic conditions for May indicate that the occurrence of meningitis is unlikely in most of the states of the country, and therefore no vigilance is advised. The agency added that conditions are still favourable for the emergence of meningitis in the far north and therefore recommended low to high vigilance.