ENVIRONMENTAL CHANGE AND MALARIA IN MAROUA, FAR NORTH CAMEROON

NDI Humphrey NGALA, Ph.D.

Department of Geography

ENS, University of Yaounde 1

Yaounde, Cameroon

Presentation outline

Introduction Methods of data collection Results Discussion Lessons Way forward

Introduction According to the WHO, malaria kills over 660 000

people mostly children less than 5 years in Africa. Over 90% of malaria related deaths occur in sub

Saharan Africa Being endemic in Cameroon, it kills over 100 000

people per year. In Cameroon, 31% of hospital consultations and

41% of hospitalizations are accounted for by malaria.

It is also responsible for 18% of patient deaths in hospitals and 41 per cent of deaths of children of less than 5 years.

Being a vector-borne disease, close links exists between the malaria mosquito (the anopheles species) and its environment and the tropics are their ideal breeding grounds.

The tropics are ideal breeding environments for mosquitoes because of the available warmth, moisture and lush vegetation conditions.

Malaria transmission is mostly seasonal and often intense in the period of rains.

Temperature and rainfall are on an increasing trend in cameroon in general, and the Far North in particular.

Study falls within theme two of the UGEC research framework which focuses on pathways through which specific global environmental changes affect urban systems.

Study area and data collection Maroua is one of the oldest cities in Cameroon,

having been founded somewhere around 1800. It is the capital of the Far North Region of

Cameroon, situated at the contact of the Mandara Mountains to its west; and the Logone plain to the east. Its original site is the confluence of the Mayo Kaliao and the Mayo Tsanaga, two important rivers which flow from the Mandara highlands.

Its population today stands at 201 371 inhabitants and it is the sixth city in Cameroon.

Mean annual rainfall in the city is 794mm while mean annual temperature is 36.35oC.

Whereas the highest temperatures are recorded in March or April, (38-40oC), the heaviest rains fall in August each year (245mm).

Sources of data: epidemiological surveillance unit of the Regional

Delegation of Public Health for the Far North; the demographic and health surveys of 2004 and

2011; the Human Development Reports for Cameroon the weather station of the Institute of Agricultural

Research for Development (IRAD) Maroua.

Key Results

Climate of Maroua is the sudano-sahelian type

Rainy season lasts 5 months and dry season last 7 months

Rainfall peaks July and August

Fig.3: Mean monthly rainfall in Maroua

Rainfall Rainfall is highly variable in Maroua. For the

data period considered, the least variation was 12% in 1999 and the highest was 27% in 1986

There is a generalized upward trend in rainfall and temperature in Maroua

Whereas increasing rainfall trend means abundant water and more breeding sites for mosquitoes, it is the strong seasonality of rainfall that is most often associated with malaria epidemics in Maroua in particular and the Far North Region in general.

Fig. 4: Rainfall trend in Maroua (25yr period)

Temperature

Mean monthly temperatures for Maroua between 2003 and 2012 are constantly high.

Notwithstanding seasonal variations often reach 9.8oC.

However, data reveals that there is a slight upward trend in temperature for the data from 2003 to 2012

Fig. 5: Mean annual temperature, 2003-2012

The atmospheric moisture and rainfall patterns are synchronized

Fig. 6: Mean monthly moisture status, Maroua

Fig. 7: Increasing malaria trend in Maroua

Environmental factors and malaria transmission The National Research Council, 2001.,

Basurko et al. 2011., & Bashar and Tuno, 2014 have all underscored the role of environmental factors especially climate in the determination of the malaria parasite activity and disease risk.

Temperature, rainfall, humidity and wind each play a role in determining the distribution of mosquito population and the incidence of malaria.

Several studies have shown that malaria transmission is often higher in higher temperatures and/or rainfall variations including those brought about by El Niño events.

These epidemics involve unstable malaria transmission often in areas generally freer of malaria like desert and highland fringes. Bouma et al., 1994, cited in the National Research Council, 2001., have shown that in Northern Pakistan (close to the Hindu Kush Mountains and the Thal desert), higher temperatures associated El Niño correlated with increased malaria incidence.

Higher malaria rates are also registered in the sudano-sahelian belt of West-Central Africa within which lies Maroua, in the rainy, and humid season.

Seasonal malaria transmission in Maroua greatly enhanced by the frequency of floods the city and its region suffers almost every year

Over the years the frequency and intensity of floods is increasing, thus more malaria transmission

Year Approximate cost (FCFA) Source

1970 Not indicated Regional Archives of Maroua, N° EN72, October 1972

1975 364,451,000 Ouédraogo and Ndiaye (2008)

1988 Not indicated Gondo et al (1997)

2005 178,000,000 Cameroon Tribune, N° 8402/4601 of 29th July 2002

Transient water and green vegetationConducive for the breeding of mosquitoes in the rainy season (June to October)

The same spot with the flood waters evaporated by the hot dry season sun

Lessons learned

Malaria transmission in Maroua is strongly seasonal in rhythm.

The increasing frequency of floods aggravates the rates of transmission.

All flood episodes are not caused by the intensities of rain storms alone, some are worsen by the collapses of the dyke on the river Logone or the Maga dam.

Although the ownership of treated mosquito bed nets is over 85%, few people use them.

Mosquitoes biting rates are increased because people mostly sit out-door during the hot evenings.

House windows are not generally fitted with mosquito nets to enable ventilation during hot nights

The death rate from malaria is also aggravated by poverty as the region ranks poorest in the country with a poverty incidence of 56.3%, above the national average of 38.7%.

Way forward

The increasing rate of floods in the Far North Region of Cameroon merits further investigation into the possible relationships these events may have meteorological events occurring elsewhere on the globe. Such may include El Niño and El Niña events.

Architectural designs to integrate malaria risk, enforceable by Local Councils within a properly decentralized set-up