RESUMO
BACKGROUND: Malaria continues to be a major cause of morbidity and mortality in Cameroon. With all efforts being made to eliminate malaria, it is imperative to describe the epidemiology of the disease in different parts of the country in order to inform control policies. This study aimed to present the differences in the prevalence and intensity of malaria and the anaemic status of children living in different areas of the North West region of Cameroon. MATERIALS AND METHODS: This study was carried out from April 2016-July 2017. Blood samples were collected from children via finger pricking. Stained thick and thin blood films were examined through microscopy (x100) to detect the presence of parasites and to estimate the geometric mean parasite density (GMPD). Packed cell volume (PCV) values were determined by micro-centrifugation. Data was analysed using SPSS to determine proportions and test for significance levels between these. RESULTS: Overall prevalence of malaria was 45.3%. Awing and Obang recorded the highest prevalence while Mankon and Nkwen recorded the lowest (p=0.01). The GMPD of infection was highly heterogeneous between the different localities (p=0.03). Age significantly affected the prevalence of malaria (p=0.02). Sex did not affect the prevalence nor the GMPD of malaria infection (p>0.05). Overall mean PCV value was 32.9±3.9. Localities in urban settings recorded the highest mean PCV values compared to those in rural settings (p=0.68). Sex and age did not affect mean PCV values (p>0.05). CONCLUSION: Malaria still remains a major problem in the North West region of Cameroon. Malaria control interventions should therefore be based on evident spatial and temporal heterogeneity of Plasmodium species in a particular area so as not to waste resources that would only be of limited effectiveness and value to the populations at risk.
RESUMO
BACKGROUND: Individuals with high intensity of Loa loa are at risk of developing serious adverse events (SAEs) post treatment with ivermectin. These SAEs have remained unclear and a programmatic impediment to the advancement of community directed treatment with ivermectin. The pathogenesis of these SAEs following ivermectin has never been investigated experimentally. The Loa/baboon (Papio anubis) model can be used to investigate the pathogenesis of Loa-associated encephalopathy following ivermectin treatment in humans. METHODS: 12 baboons with microfilarial loads > 8,000mf/mL of blood were randomised into four groups: Group 1 (control group receiving no drug), Group 2 receiving ivermectin (IVM) alone, Group 3 receiving ivermectin plus aspirin (IVM + ASA), and Group 4 receiving ivermectin plus prednisone (IVM + PSE). Blood samples collected before treatment and at Day 5, 7 or 10 post treatment, were analysed for parasitological, hematological and biochemical parameters using standard techniques. Clinical monitoring of animals for side effects took place every 6 hours post treatment until autopsy. At autopsy free fluids and a large number of standard organs were collected, examined and tissues fixed in 10% buffered formalin and processed for standard haematoxylin-eosin staining and specific immunocytochemical staining. RESULTS: Mf counts dropped significantly (p<0.05) in all animals following ivermectin treatment with reductions as high as (89.9%) recorded; while no significant drop was observed in the control animals. Apart from haemoglobin (Hb) levels which recorded a significant (p = 0.028) drop post treatment, all other haematological and biochemical parameters did not show any significant changes (p>0.05). All animals became withdrawn 48 hours after IVM administration. All treated animals recorded clinical manifestations including rashes, itching, diarrhoea, conjunctival haemorrhages, lymph node enlargement, pinkish ears, swollen face and restlessness; one animal died 5 hours after IVM administration. Macroscopic changes in post-mortem tissues observed comprised haemorrhages in the brain, lungs, heart, which seen in all groups given ivermectin but not in the untreated animals. Microscopically, the major cellular changes seen, which were present in all the ivermectin treated animals included microfilariae in varying degrees of degeneration in small vessels. These were frequently associated with fibrin deposition, endothelial changes including damage to the integrity of the blood vessel and the presence of extravascular erythrocytes (haemorrhages). There was an increased presence of eosinophils and other chronic inflammatory types in certain tissues and organs, often in large numbers and associated with microfilarial destruction. Highly vascularized organs like the brain, heart, lungs and kidneys were observed to have more microfilariae in tissue sections. The number of mf seen in the brain and kidneys of animals administered IVM alone tripled that of control animals. Co-administration of IVM + PSE caused a greater increase in mf in the brain and kidneys while the reverse was noticed with the co-administration of IVM + ASA. CONCLUSIONS: The treatment of Loa hyper-microfilaraemic individuals with ivermectin produces a clinical spectrum that parallels that seen in Loa hyper-microfilaraemic humans treated with ivermectin. The utilization of this experimental model can contribute to the improved management of the adverse responses in humans.