Background and Methods: Schistosomiasis is debilitating and reported to impair immune responsiveness of infected hosts. In Cameroon, mass drug administration (MDA) is used in schoolchildren to reduce transmission of S. haematobium and S. mansoni. The effects of MDA and the impact of schistosomiasis on the titers of antibodies in vaccinated children have been poorly studied. We therefore assessed the prevalence of schistosomiasis in schoolchildren, eight months after MDA, in two locations: Barombi Koto (BK), endemic for S. haematobium (N = 169) and Yoro (Y), endemic for S. mansoni (N = 356). Age, gender, residence time and frequency of contact with river water were assessed as risk factors for infection and morbidity in both localities. In 70 schoolchildren from BK and 83 from Y, ultrasound was used to assess morbidity according to the WHO guidelines. Evaluation of measles antibodies was performed in previously vaccinated schoolchildren (14 with S. haematobium and 12 egg-negative controls from BK and 47 with S. mansoni and12 egg-negative controls from Y).Principal Findings and conclusions: The prevalence of S. haematobium was 25. 4% in BK (43/169) and 34.8% for S. mansoni in Y (124/356), indicating the persistent transmission of schistosomiasis despite MDA. Older age (AOR 1.31; 95%CI 1.12–1.54) and higher frequencies of exposure to river water (AOR 1.99; 95%CI 1.03–3.86) were identified as risks for infection in BK whereas only older age (OR 1.15; 95%CI 1.04–1.27) was a risk for infection in Y. Bladder pathology (score 2 to 5) was observed in 29.2% (7/24) of egg-positive children in BK and liver pathology (pattern C) in 31.1% (19/61) of egg-positive children in Y. There was a positive correlation between S. haematobium egg burden and bladder pathology (AOR 1.01; 95% CI 0.99–1.02) and positive correlation between S. mansoni-driven liver pathology and female gender (AOR 3.01; 95% CI 0.88–10.26). Anti-measles antibodies in vaccinated children were significantly lower in S. mansoni-infected when compared to egg-negative controls (p = 0.001), which was not observed in the S. haematobium-infected group from BK. Our results demonstrate a questionable efficacy of MDA alone in halting schistosomiasis transmission and confirm a possible immunomodulatory effect of S. mansoni on response to vaccines.

BackgroundThe efficacy of amodiaquine (AQ), sulphadoxine-pyrimethamine (SP) and the combination of SP+AQ in the treatment of Cameroonian children with clinical malaria was investigated. The prevalence of molecular markers for resistance to these drugs was studied to set the baseline for surveillance of their evolution with time.MethodsSeven hundred and sixty children aged 6-59 months with uncomplicated falciparum malaria were studied in three ecologically different regions of Cameroon - Mutengene (littoral equatorial forest), Yaoundé (forest-savannah mosaic) and Garoua (guinea-savannah). Study children were randomized to receive either AQ, SP or the combination AQ+SP. Clinical outcome was classified according to WHO criteria, as either early treatment failure (ETF), late clinical failure (LCF), late parasitological failure (LPF) or adequate clinical and parasitological response (ACPR). The occurrence of mutations in pfcrt, pfmdr1, dhfr and dhps genes was studied by either RFLP or dot blot techniques and the prevalence of these mutations related to parasitological and therapeutic failures.ResultsAfter correction for the occurrence of re-infection by PCR, ACPRs on day 28 for AQ, SP and AQ+SP were 71.2%, 70.1% and 80.9%, in Garoua, 79.2%, 62.5%, and 81.9% in Mutengene, and 80.3%, 67.5% and 76.2% in Yaoundé respectively. High levels of Pfcrt 76T (87.11%) and Pfmdr1 86Y mutations (73.83%) were associated with quinoline resistance in the south compared to the north, 31.67% (76T) and 22.08% (86Y). There was a significant variation (p < 0.001) of the prevalence of the SGK haplotype between Garoua in the north (8.33%), Yaoundé (36.29%) in the savannah-forest mosaic and Mutengene (66.41%) in the South of Cameroon and a weak relation between SGK haplotype and SP failure. The 540E mutation on the dhps gene was extremely rare (0.3%) and occurred only in Mutengene while the pfmdr1 1034K and 1040D mutations were not detected in any of the three sites.ConclusionIn this study the prevalence of molecular markers for quinoline and anti-folate resistances showed high levels and differed between the south and north of Cameroon. AQ, SP and AQ+SP treatments were well tolerated but with low levels of efficacy that suggested alternative treatments were needed in Cameroon since 2005.

Background. In Cameroon, both Artesunate-amodiaquine (AS/AQ) and artemether-lumefantrine (AL) are used as first-line treatment against uncomplicated malaria in line with the WHO recommendations. We compared the efficacy and safety of both therapeutic combinations and determined the prevalence of drug resistance conferring mutations in three parasite genes. Methods. One hundred and fifty acute malaria patients between six months and 14 years of age were randomized to receive standard doses of either AS/AQ (73) or AL (77) and followedup for 28 days. Outcome of treatment was according to the standard WHO classification. DNA samples from pretreatment parasite isolates were used to determine the prevalence of resistant mutations in the pfcrt, pfmdr1, and dhfr genes. Results. Both drug combinations induced rapid clearance of parasites and malaria symptoms. PCR-corrected cure rates were 100% and 96.4% for AL. The combinations were well tolerated. Major haplotypes included CVIET (71%), CVMNT (25%) for the pfcrt; SND (100%) for the pfmdr1; IRN (79, 8%), NCS (8.8%), and mixed haplotype (11, 8%) for the dhfr. Conclusion. Both AS/AQ and AL were highly effective and well tolerated for the treatment of uncomplicated falciparum malaria in Ngaoundere, Cameroon. High prevalence of mutant pfcrt alleles confirms earlier observations. Long-term monitoring of safety and efficacy and molecular markers is highly solicited.

Immunoglobulin G specific responses againstPlasmodium falciparummerozoite antigens such as the merozoite surface protein 3 (MSP3) and UB05 are known to play critical roles in parasitemia control and protection from symptomatic illness. However when there is intense perennial malaria transmission coupled with concurrent infection with the human immunodeficiency virus type 1 (HIV), knowledge of IgG antibody response profiles is limited. In this study we assessed the impact of dual HIV-Malaria infections on IgG subclass responses to MSP3 (QβMSP3) and UB05 (QβUB05) in individuals living in two areas of Cameroon differing in transmission intensity. We observed differences in antigen specific IgG and IgG subclass responses which was dependent upon the antigen type, malaria transmission intensity, HIV infection, malaria infection and dual HIV-malaria infections. Individuals living in high malaria transmission areas irrespective of HIV or malaria status had significantly higher IgG responses to both antigens (P=0.0001 for QβMSP3, P=0.0001 for QβUB05) than their counterpart from low transmission areas. When dual HIV-Malaria infection is considered significantly higher QβMSP3 specific IgG1 (P=0.0001) and IgG3 (P=0.04) responses in double negative individuals was associated with protection against malaria in low transmission areas. Superior QβUBO5 specific IgG1 responses (P=0.0001) in double negative individuals were associated with protection in high transmission areas in contrast to significantly higher IgG3 responses to QβUB05 (P=0.0001) which were more relevant to protection in low malaria transmission areas in the same population. Thus, understanding immune responses to QβUB05 and QβMSP3 could facilitate the development of immunotherapeutic strategies suitable for areas differing in malaria transmission intensity.

Background: This study aimed to investigate the association of plasma levels of IL-33, a mucosal alarmin known to elicit type-2 immunity, with infection and liver fibrosis profiles of school children from an endemic area for Schistosoma mansoni, malaria and hepatitis (B & C) in rural Cameroon.Methods: A cross-sectional study enrolling schoolchildren from 5 public schools was conducted. Single schistosomiasis, malaria and hepatitis infections or co-infections were assessed by kato katz, microscopy, and rapid diagnostic tests, respectively. Hepatic fibrosis was assessed by ultrasound according to WHO Niamey guidelines and plasma levels of Interleukin 33 were determined by ELISA. All statistics were performed using R studio software.Principal findings: We found a prevalence of 13.5% (37/275), 18.2% (50/275), and 8% (22/275), respectively for schistosomiasis, malaria and hepatitis (B or C) single infections. Only 7.6% (21/275) of co-infections were reported. Although Plasma IL-33 showed a minimal negative risk for schistosomiasis infection (AOR 0.99; 95% CI 0.97–1.01), S. mansoni infected participants had lower levels of plasma IL-33 (p = 0.003) which decreased significantly as eggs burdens increased (p = 0.01) with a negative Pearson coefficient of r = −0.22. Hepatic fibrosis occurred in 47.3% (130/275) of our study population independently from plasma levels of IL-33 (AOR 1.00; 95% CI 0.99–1.01).Conclusion/Significance: Our data failed to show an association between plasma IL-33 levels and liver disease but convincingly report on a negative association between plasma IL-33 levels and schistosomiasis infection and egg burden in school children from a polyparasitic schistosomiasis endemic area.