Although the number of malaria cases reported in this study was limited to the population of inhabitants seeking for medical care in hospitals, with no consideration for those who practice auto-medication, the data shows that the incidence of malaria is high in both MHD and THD. The high burden of malaria in Muyuka Health District reported in this study, confirms previous findings where 98.5% of febrile children admitted in Muyuka District Hospital had malaria . The population of MHD and THD have received mass distribution of long-lasting insecticide treated bed nets three times in 2011 , 2015 and 2019 simultaneously , however discrepancies in the effective usage abound, which can have a toll on the number of malaria cases. Also studies on the spread of resistant alleles of Anopheles funestus in Tiko and in Meanja, found in Muyuka, reported similar vector composition (Anopheles gambiae, Anopheles funestus, Anopheles coluzzii, Anopheles melas, Anopheles hancocki, Anopheles nili and Anopheles ziemanni) with differences in relative abundance  and Anopheles melas which is common in coastal areas, does not contribute to malaria transmission in Tiko . The differences in relative abundance may also affect the number of malaria cases. Mean yearly humidity showed a strong negative correlation with number of malaria cases in MHD, (an inland setting). This implies that in an inland area, higher humidity leads to lower number of malaria cases and inland areas are known to suffer from frequent fluctuation in humidity compared to coastal areas which enjoy a fairly stable humidity as a result of constant evaporation of water from the sea . This observation of a negative correlation between humidity and the number of malaria cases was also true for Tiko, a coastal town but was not significant. Probably because the humidity in coastal areas is fairly constant all year round, as a result of the buffering effect of the sea . This is explained by the fact that Humidity is the amount of water vapor in the air and is inversely proportional to temperature. So in an inland setting where there is rapid increase in temperature during the day, the humidity is lower and vice versa at night whereas in the coastal setting temperature increases more slowly due to the fact that the sea absorbs heat at a slower rate than land and also releases heat at night at that same rate, this keeps the humidity of the environment mild and therefore humidity tend not to have so much impact on the number of malaria cases. Similar results of a negative correlation between humidity and malaria incidence have been recorded in a study carried out in Kahnouj (Iran) . Other studies have shown that relative humidity and malaria incidence have a positive correlation  while others show that they have no significant correlation .
Mean seasonal temperature showed a moderate positive correlation with number of malaria cases in THD, a typical coastal setting. This implies that high temperatures lead to increase number of malaria cases, and similar results have been reported in Bolifamba, which is located in Fako Division, South West Region of Cameroon . It is thought that increase temperature by 1 °C in the range of 18-26 °C increases the life span of a mosquito by more than a week , leading to increase number of mosquitos and also shortens the intrinsic incubation period of malaria parasite within the mosquito vector , which leads to increased number of infective bites and increased malaria prevalence. However, in Muyuka Health District, a very weak negative correlation was observed between the number of malaria cases and mean seasonal temperature. Other studies have also shown a significant positive correlation between malaria incidence and temperature [22, 26,27,28,29].
Mean seasonal rain fall in Tiko Health District also showed a moderately negative correlation with number of malaria cases. This is in agreement with the fact that excess rainfall washes off mosquito breeding sites and reduces malaria prevalence . This was contrary to what was observed in Muyuka Health District, an inland setting where a weak positive correlation was observed between seasonal rainfall and number of malaria case. This can be explained by the fact that coastal areas usually enjoy more rain fall from convectional rainfall, compared to inland areas like Muyuka Health District. Consequently, Muyuka may have less episodes of excessive rain fall, which can wash off the mosquito breeding sites, rather the less rainfall creates new breeding sites by filling up potholes, which explains the positive correlation. Another study has also reported that rainfall has a decreasing effect on Plasmodium vivax prevalence .
Finally, prediction of future number of malaria cases was done using the simple seasonal model following the trend of malaria incidence for a 7-year period. These predictions were for two years after the study period (2018 and 2019). The observed and fitted values were well fitted (Fig. 7) with a stationary R squared value of 0.545 for MHD and 0.732 for THD. The prediction showed a higher number of malaria cases in 2018 and 2019 (6842 for both years) than the number observes (3167 in 2018 and 2848 in 2019) in MHD. In THD, the model predicted less than what was observed. In THD the model showed that there will be 6738 cases of malaria in 2018 and 2019 as opposed to 7327 cases that was observed in 2018 and 21,735 in 2019. These predictions are informative but far from accuracy as a result of other anthropogenic activities which influences the number of malaria cases, such as large-scale use of long-lasting insecticide bed nets, auto-medication, lots of outdoor activities which carry on late into the night during end of year festivities, amongst other. Future models should consider other parameters that influence the incidence of malaria.