Anopheles gambiae larvae's ability to grow and emerge in water containing lethal concentrations of clothianidin, acetamiprid, or imidacloprid is consistent with cross-resistance to neonicotinoids.

BACKGROUND: For decades, various agrochemicals have been successfully repurposed for mosquito control. However, preexisting resistance caused in larval and adult populations by unintentional pesticide exposure or other cross-resistance mechanisms poses a challenge to the efficacy of this strategy. A better understanding of larval adaptation to the lethal and sublethal effects of residual pesticides in aquatic habitats would provide vital information for assessing the efficacy of repurposed agrochemicals against mosquitoes. METHODS: We reared field-collected mosquito larvae in water containing a concentration of agrochemical causing 100% mortality in susceptible mosquitoes after 24 h (lethal concentration). Using this experimental setup, we tested the effect of lethal concentrations of a pyrrole (chlorfenapyr, 0.10 mg/l), a pyrethroid (deltamethrin, 1.5 mg/l), and three neonicotinoids including imidacloprid (0.075 mg/l), acetamiprid (0.15 mg/l), and clothianidin (0.035 mg/l) on mortality rates, growth, and survival in third-instar larvae of the two sibling species Anopheles gambiae and Anopheles coluzzii collected from Yaoundé, Cameroon. RESULTS: We found that An. gambiae and An. coluzzii larvae were susceptible to chlorfenapyr and were killed within 24 h by a nominal concentration of 0.10 mg/l. Consistent with strong resistance, deltamethrin induced low mortality in both species. Lethal concentrations of acetamiprid, imidacloprid, and clothianidin strongly inhibited survival, growth, and emergence in An. coluzzii larvae. By contrast, depending on the active ingredient and the population tested, 5-60% of immature stages of An. gambiae were able to grow and emerge in water containing a lethal concentration of neonicotinoids, suggesting cross-resistance to this class of insecticides. CONCLUSIONS: These findings corroborate susceptibility profiles observed in adults and suggest that unintentional pesticide exposure or other cross-resistance processes could contribute to the development of resistance to neonicotinoids in some Anopheles populations.

Adult mosquitoes of the sibling species Anopheles gambiae and Anopheles coluzzii exhibit contrasting patterns of susceptibility to four neonicotinoid insecticides along an urban-to-rural gradient in Yaoundé, Cameroon.

BACKGROUND: Neonicotinoids are potential alternatives for controlling pyrethroid-resistant mosquitoes, but their efficacy against malaria vector populations of sub-Saharan Africa has yet to be investigated. The aim of the present study was to test the efficacy of four neonicotinoids against adult populations of the sibling species Anopheles gambiae and Anopheles coluzzii sampled along an urban-to-rural gradient. METHODS: The lethal toxicity of three active ingredients for adults of two susceptible Anopheles strains was assessed using concentration-response assays, and their discriminating concentrations were calculated. The discriminating concentrations were then used to test the susceptibility of An. gambiae and An. coluzzii mosquitoes collected from urban, suburban and rural areas of Yaoundé, Cameroon, to acetamiprid, imidacloprid, clothianidin and thiamethoxam. RESULTS: Lethal concentrations of neonicotinoids were relatively high suggesting that this class of insecticides has low toxicity against Anopheles mosquitoes. Reduced susceptibility to the four neonicotinoids tested was detected in An. gambiae populations collected from rural and suburban areas. By contrast, adults of An. coluzzii that occurred in urbanized settings were susceptible to neonicotinoids except acetamiprid for which 80% mortality was obtained within 72 h of insecticide exposure. The cytochrome inhibitor, piperonyl butoxide (PBO), significantly enhanced the activity of clothianidin and acetamiprid against An. gambiae mosquitoes. CONCLUSIONS: These findings corroborate susceptibility profiles observed in larvae and highlight a significant variation in tolerance to neonicotinoids between An. gambiae and An. coluzzii populations from Yaoundé. Further studies are needed to disentangle the role of exposure to agricultural pesticides and of cross-resistance mechanisms in the development of neonicotinoid resistance in some Anopheles species.

Vegetable oil-based surfactants are adjuvants that enhance the efficacy of neonicotinoid insecticides and can bias susceptibility testing in adult mosquitoes.

BACKGROUND: The standard operating procedure for testing the susceptibility of adult mosquitoes to neonicotinoid or butenolide insecticides recommends using a vegetable oil ester (Mero) as a surfactant. However, there is growing evidence that this adjuvant contains surfactants that can enhance insecticide activity, mask resistance and bias the bioassay. METHODOLOGY/PRINCIPAL FINDINGS: Using standard bioassays, we tested the effects of commercial formulations of vegetable oil-based surfactants similar to Mero on the activity of a spectrum of active ingredients including four neonicotinoids (acetamiprid, clothianidin, imidacloprid and thiamethoxam) and two pyrethroids (permethrin and deltamethrin). We found that three different brands of linseed oil soap used as cleaning products drastically enhanced neonicotinoid activity in Anopheles mosquitoes. At 1% (v/v), the surfactant reduced the median lethal concentration, LC50, of clothianidin more than 10-fold both in susceptible and in resistant populations of Anopheles gambiae. At 1% or 0.5% (v/v), linseed oil soap restored the susceptibility of adult mosquitoes fully to clothianidin, thiamethoxam and imidacloprid and partially to acetamiprid. By contrast, adding soap to the active ingredient did not significantly affect the level of resistance to permethrin or deltamethrin suggesting that vegetable oil-based surfactants specifically enhance the potency of some classes of insecticides. CONCLUSIONS/SIGNIFICANCE: Our findings indicate that surfactants are not inert ingredients, and their use in susceptibility testing may jeopardize the ability to detect resistance. Further research is needed to evaluate the potential, the limitations and the challenges of using some surfactants as adjuvants to enhance the potency of some chemicals applied in mosquito control.

Vegetable oil surfactants are synergists that can bias neonicotinoid susceptibility testing in adult mosquitoes.

Background: The standard operating procedure for testing the susceptibility of adult mosquitoes to clothianidin, a neonicotinoid, recommends using a vegetable oil ester as surfactant. However, it has not yet been determined if the surfactant is an inert ingredient or if it can act as a synergist and bias the test. Methodology/Principal Findings: Using standard bioassays, we tested the synergistic effects of a vegetable oil surfactant on a spectrum of active ingredients including four neonicotinoids (acetamiprid, clothianidin, imidacloprid and thiamethoxam) and two pyrethroids (permethrin and deltamethrin). Three different formulations of linseed oil soap used as surfactant were far more effective than the standard insecticide synergist piperonyl butoxide in enhancing neonicotinoid activity in Anopheles mosquitoes. At the concentration used in the standard operating procedure (1% v/v), vegetable oil surfactants lead to more than 10-fold reduction in lethal concentrations, LC 50 and LC 99 , of clothianidin in a multi-resistant field population and in a susceptible strain of Anopheles gambiae . At 1% or 0.5% (v/v), the surfactant restored susceptibility to clothianidin, thiamethoxam and imidacloprid and increased mortality to acetamiprid from 43 ± 5.63% to 89 ± 3.25% (P<0.05) in resistant mosquitoes. By contrast, linseed oil soap had no effect on the level of resistance to permethrin and deltamethrin suggesting that the synergism of vegetable oil surfactants may be specific to neoniconoids. Conclusions/Significance: Our findings indicate that vegetable oil surfactants are not inert ingredients in neonicotinoid formulations, and their synergistic effects undermine the ability of standard testing procedures to detect early stages of resistance.

Enhancing the efficacy of neonicotinoids against mosquitoes and overcoming resistance issues.

Background: Neonicotinoids are potential alternatives for targeting pyrethroid-resistant mosquitoes, but their efficacy against malaria vector populations of Sub-Saharan Africa has yet to be investigated. Here we tested and compared the efficacy of four neonicotinoids alone or in combination with a synergist against two major vectors of Plasmodium . Results: Using standard bioassays, we first assessed the lethal toxicity of three active ingredients against adults of two susceptible Anopheles strains and we determined discriminating doses for monitoring susceptibility in wild populations. We then tested the susceptibility of 5532 Anopheles mosquitoes collected from urban and rural areas of Yaoundé, Cameroon, to discriminating doses of acetamiprid, imidacloprid, clothianidin and thiamethoxam. We found that in comparison with some public health insecticides, neonicotinoids have high lethal concentration, LC 99 , reflecting their low toxicity to Anopheles mosquitoes. In addition to this reduced toxicity, resistance to the four neonicotinoids tested was detected in An. gambiae populations collected from agricultural areas where larvae are intensively exposed to crop-protection neonicotinoids. However, adults of another major vector that occurred in urbanized settings, An. coluzzii , were fully susceptible to neonicotinoids except acetamiprid for which 80% mortality was obtained within 72 h of insecticide exposure. Importantly, the cytochrome inhibitor, piperonyl butoxide (PBO), was very effective in enhancing the activity of clothianidin and acetamiprid providing opportunities to create potent neonicotinoid formulations against Anopheles . Conclusion: These findings suggest that to successfully repurpose agricultural neonicotinoids for malaria vector control, it is essential to use formulations containing synergists such as PBO or surfactants to ensure optimal efficacy.

Chronic exposure of mosquito larvae to pesticide residues endangers a new generation of agrochemicals repurposed for malaria prevention.

Agrochemicals have been successfully repurposed to control mosquitoes worldwide, but pesticides used in agriculture challenge their effectiveness by contaminating surface waters and helping larval populations develop resistance. Thus, knowledge of the lethal and sublethal effects of residual pesticide exposure on mosquitoes is critical for selecting effective insecticides. Here we implemented a new experimental approach to predict the efficacy of agricultural pesticides newly repurposed for malaria vector control. We mimicked insecticide resistance selection as it occurs in contaminated aquatic habitats by rearing field-collected mosquito larvae in water containing a dose of insecticide capable of killing individuals from a susceptible strain within 24 h. We then simultaneously monitored short-term lethal toxicity within 24 h and sublethal effects for 7 days. We found that due to chronic exposure to agricultural pesticides, some mosquito populations are currently pre-adapt to resist neonicotinoids if those were used in vector control. Larvae collected from rural and agricultural areas where neonicotinoid formulations are intensively used for insect pest management were able to survive, grow, pupate and emerge in water containing a lethal dose of acetamiprid, imidacloprid or clothianidin. These results emphasize the importance of addressing exposure of larval populations to formulations applied in agriculture prior to using agrochemicals against malaria vectors.

High infection rates for onchocerciasis and soil-transmitted helminthiasis in children under five not receiving preventive chemotherapy: a bottleneck to elimination.

BACKGROUND: The current mainstay for control/elimination of onchocerciasis and soil-transmitted helminthiasis (STH) relies on ivermectin- and mebendazole/albendazole-based preventive chemotherapies. However, children under five years of age have been excluded in both research activities and control programs, because they were believed to have insignificant infection rates. There is therefore a need for up-to-date knowledge on the prevalence and intensity of STH and onchocerciasis infections in this age group. This study aimed at assessing the rates and intensities of onchocerciasis and STH infections in children under five years of age who are excluded from ivermectin- or mebendazole/albendazole-based preventive chemotherapies. METHODS: A series of cross-sectional surveys was conducted in four Health Districts in the Centre and Littoral Regions of Cameroon between 2018 and 2019. All subjects aged 2 to 4 years, were screened for prevalence (or infection rate) and intensity [number of eggs per gram of stool (epg) or number of microfilariae per skin snip (mf/ss)] of STH and onchocerciasis infections respectively using the Kato-Katz and skin snip methodologies. Chi-square and the non-parametric tests (Mann Whitney and Kruskal Wallis) were used to compare infection rates and intensities of infections between Health Districts and genders, respectively. RESULTS: A total of 421 children were enrolled in this study. The overall prevalence of onchocerciasis was 6.6% [95% confidence interval (CI): 4.3‒9.9], ranging from 3.6% (in the Ntui Health District) to 12.2% (in the Bafia Health District). The intensity of infection ranged from 0.5 to 46 microfilariae per skin snip [median: 5; interquartile range (IQR): 2.25‒8.5]. The overall prevalence of STH was 9.6% (95% CI: 6.5‒13.9), with a high infection rate (29.6%) in the Akonolinga Health District. Two STH species (Ascaris lumbricoides and Trichuris trichiura) were found among infected individuals. The median intensities of STH infections were 1,992 epg (IQR: 210‒28,704) and 96 epg (IQR: 48‒168) for A. lumbricoides and T. trichiura, respectively. CONCLUSIONS: This study reveals that children < 5 years of age are highly infected with STH and onchocerciasis, and could contribute to the spread of these diseases, perpetuating a vicious circle of transmission and hampering elimination efforts. These findings reveal the urgent need to provide (or scale) treatments (likely pediatric formulations) to these preschool-aged children, especially in areas of high transmission, to accelerate efforts to reach WHO 2030 target.

Molecular epidemiology of Enteroviruses and Rhinoviruses in patients with acute respiratory infections in Yaounde, Cameroon.

BACKGROUND: Acute respiratory infections (ARI) are associated with a huge morbidity and mortality worldwide. Rhinoviruses (RVs) and Enteroviruses (EVs) are recognized as leading causes of ARI. OBJECTIVES: The present study describes the molecular epidemiology of RVs and EVs in Cameroon over a 3-year surveillance period. METHODS: From September 2011 to October 2014, nasopharyngeal swabs were collected from patients with influenza-like illness (ILI) and severe acute respiratory infections (SARI). Two sub-genomic regions of the EVs and RVs were targeted for molecular characterization. These included the most conserved 5'-untranslated region (5'UTR) and the viral protein 4/viral protein 2 transition region (VP4/VP2). RESULTS: A total of 974 samples were collected. Children ≤5 years accounted for 85.7% (835/974) of all participants. Among them, 160 (16.4%) were positive for RVs and/or EVs. RVs and/or EVs were significantly more identified in ILI compared to SARI patients (P = .015). Both viruses co-circulated all year long with a marked increase of occurrence during rainy and cold season. All RV species were found to circulate in Cameroon, with 6, 10 and 6 virus types belonging to the RV-A, RV-B and RV-C, respectively. EV species identified comprised EV-A (1 Coxsackie virus A5), EV-B (1 Coxsackie virus A9 and 2 Coxsackie virus B1) and EV-C (1 EV-C117). CONCLUSIONS: This study indicates a strong year-round occurrence of EV and RV associated respiratory infections in Cameroon. Molecular characterization identified a wide variety of RVs and EVs in patients with ARI in Cameroon.

Saponin with antibacterial activity from the roots of Albizia adianthifolia.

An unprecedented saponin is being reported herein together with five known compounds from the methanol extract of the roots of Albizia adianthifolia. The metabolites were obtained over repeated open column chromatography methods and spectroscopic followed by spectrometric techniques. The isolated compounds were tested against eleven Gram-negative bacteria including multidrug resistant strains. The results revealed considerable inhibition of the new saponin against the studied bacteria with MIC values ranging from 16 to 128 µg/mL.

Analysis of Haemophilus species in patients with respiratory tract infections in Yaoundé, Cameroon.

OBJECTIVES: To identifyHaemophilus species and characterize antimicrobial susceptibility of isolates from patients with respiratory tract infections (RTIs) in Cameroon. METHODS: Isolates (n = 95) were from patients with RTIs obtained from two Hospitals in Yaoundé, Cameroon. Isolates were identified by biochemical assay, PCR-based method, MALDI-TOF and whole genome sequencing. Antibiotic minimum inhibitory concentrations were determined by E-test. RESULTS: H. influenzae was the most prevalent species varying from 76.8% to 84.2% according to different methods. The isolates were mainly nontypable (n = 70, 96%). Three isolates of H. influenzae were capsulated (b, e and f). The isolates were genetically diverse and 40 unique sequence types were identified including 11 new ones. Resistance to ampicillin was observed among 55.3% (52/94) and 9% (14/52) produced TEM-1 ß-lactamase. PBP3 mutations occurred in 57.7% of ampicillin resistant isolates (30/52). Eleven isolates were chloramphenicol resistant with 80% producing chloramphenicol acetyltransferase (8/10). Four Haemophilus isolates were rifampicin resistant with two mutations in rpoB gene. Five isolates were ciprofloxacin resistant and harbored mutations in the quinolone resistance determining regions of gyrA and parC genes. CONCLUSION: H. influenzae isolates are highly diverse and show high levels of antibiotic resistance. H. influenzae serotype b is still circulating in the post-vaccination era.

Antibiotic Resistance Profile of Uropathogenic Bacteria in Diabetic Patients at the Bafoussam Regional Hospital, West Cameroon Region.

Background Urinary tract infections constitute a major public health concern. The aim of the study is to look into the antibiotic sensitivity profile of uropathogenic bacteria among diabetic individuals in the Diabetology Unit of the Bafoussam Regional Hospital, West Cameroon. Methods A cross-sectional study was carried out in Bafoussam Regional Hospital. Urine was collected in a sterile jar previously labelled. The microorganisms were isolated on agar medium and their final identification was carried out on the API20E gallery. The antibiogram was performed using agar diffusion methods. Results Escherichia coli (25.30%) and Staphylococcus aureus (19.27%) were the most noticed species in the diabetic patients, whereas Escherichia coli (32.00%) and Klebsiella pneumoniae (22.00%) were the most noticed in non-diabetic patients. There was a significant association between antibiotic resistance and diabetic status (for ceftriaxone: X2 = 23.78 and P-value < 0.001; for cefixime: X2 = 19.31 and P-value < 0.001; for ceftazidime: X2 = 9.45 and P-value = 0.008; for cefotaxime: X2 = 10.97 and P-value = 0.004; for cefepime: X2 = 27.93 and P-value < 0.001; and for ciprofloxacin: X2 = 11.13 and P-value = 0.003). Multidrug resistance rate against some bacterial species were higher in diabetic patients (62.50% for Escherichia coli, 63.16% for Klebsiella pneumoniae, and 78.57% for Staphylococcus aureus) compared with non-diabetic patients (37.50% for Escherichia coli, 36.84% for Klebsiella pneumoniae, and 21.43% for Staphylococcus aureus). Conclusions  This study revealed that there is an association between antibiotic resistance and diabetic status. Research and interventions must be focused on the elderly diabetic population in order to fight against the occurrence of drug-resistant uropathogenes.

Phylogenetic variability of Human Metapneumovirus in patients with acute respiratory infections in Cameroon, 2011-2014.

BACKGROUND: Identified in 2001, Human Metapneumovirus (HMPV) is a Pneumovirus associated with acute lower and upper respiratory infections in all age groups and especially in newborns, elderly and immunocompromised subjects. Data are still limited in sub-Saharan African countries genetic characterization of this respiratory virus. This study reports the genetic variability of HMPV strains in Cameroonian children for 3 consecutive epidemic seasons (September 2011-October 2014). METHODS: A prospective surveillance was conducted to identify inpatient and outpatient children less than 15 years with respiratory symptoms ≤5 days. The nasopharyngeal samples were tested for HMPV using a multiplex polymerase chain reaction. Viral distribution and demographic data were analyzed statistically. Positive samples for HMPV were amplified by semi-nested polymerize chain reaction and then partially sequenced at the G gene. Phylogenetic analyzes were performed on the partial nucleotide and protein sequences of the G gene. RESULTS: From September 2011 to October 2014, 822 children under 15 years were enrolled in the study. HMPV was identified in each of 3.9% (32/822) of children. HMPV were detected throughout the year. HMPV-A (73.3%; 11/15) was predominant compared to HMPV-B (26.7; 4/15). Cameroonian HMPV strains are grouped among the members of genotype A2b (for HMPV-A), B1 and B2 (for HMPV-B). CONCLUSION: This study suggests that about 4% of ARI recorded in children in Cameroon are caused by HMPV. The present study is also the first report on the genetic variability of the G gene of HMPV strains in the region. Although this work partially fills gaps for some information, additional studies are required to clarify the molecular epidemiology and evolutionary pattern of HMPV in sub-Saharan Africa in general and more particularly in Cameroon.

Molecular characterization of measles virus strains circulating in Cameroon during the 2013-2016 epidemics.

The first genotyping data on measles virus (MeV) strains in Cameroon dates from 1994, while other studies were realized in 2001 and 2011 with the establishment of MeV virological surveillance. However, the genetic data of MeV strains circulating in Cameroon remains fragmented and concentrated in certain regions, hence the need for an update. The objective of this study was to have recent data on MeV genotypes circulating in Cameroon. Ninety throat swabs collected during recent measles outbreaks were analyzed by MeV genotyping RT-PCR using the nucleoprotein gene N. The resulting sequences were analyzed on the basis of 450 nucleotides with MEGA 7 software. Overall genome analysis was performed on 40/90 sequences. The strains were from all ten regions and all belonged to cluster 1 of genotype B3. The genotype B3 has been circulating in Cameroon for long periods of time; efforts must be made in immunization for its elimination.

In Vitro Assessment of Anthelmintic Activities of Rauwolfia vomitoria (Apocynaceae) Stem Bark and Roots against Parasitic Stages of Schistosoma mansoni and Cytotoxic Study.

Schistosomiasis is a Neglected Tropical Diseases which can be prevented with mass deworming chemotherapy. The reliance on a single drug, praziquantel, is a motivation for the search of novel antischistosomal compounds. This study investigated the anthelmintic activity of the stem bark and roots of Rauwolfia vomitoria against two life stages of Schistosoma mansoni. Both plant parts were found to be active against cercariae and adult worms. Within 2 h of exposure all cercariae were killed at a concentration range of 62.5-1000 µg/mL and 250-1000 µg/mL of R. vomitoria stem bark and roots, respectively. The LC50 values determined for the stem bark after 1 and 2 h of exposure were 207.4 and 61.18 µg/mL, respectively. All adult worms exposed to the concentrations range of 250-1000 µg/mL for both plant parts died within 120 h of incubation. The cytotoxic effects against HepG2 and Chang liver cell assessed using MTT assay method indicated that both plant extracts which were inhibitory to the proliferation of cell lines with IC50 > 20 µg/mL appear to be safe. This report provides the first evidence of in vitro schistosomicidal potency of R. vomitoria with the stem bark being moderately, but relatively, more active and selective against schistosome parasites. This suggests the presence of promising medicinal constituent(s).

New Mycobacterium tuberculosis Complex Sublineage, Brazzaville, Congo.

Tuberculosis is a leading cause of illness and death in Congo. No data are available about the population structure and transmission dynamics of the Mycobacterium tuberculosis complex strains prevalent in this central Africa country. On the basis of single-nucleotide polymorphisms detected by whole-genome sequencing, we phylogenetically characterized 74 MTBC isolates from Brazzaville, the capital of Congo. The diversity of the study population was high; most strains belonged to the Euro-American lineage, which split into Latin American Mediterranean, Uganda I, Uganda II, Haarlem, X type, and a new dominant sublineage named Congo type (n = 26). Thirty strains were grouped in 5 clusters (each within 12 single-nucleotide polymorphisms), from which 23 belonged to the Congo type. High cluster rates and low genomic diversity indicate recent emergence and transmission of the Congo type, a new Euro-American sublineage of MTBC.

Mechanically produced schistosomula as a higher-throughput tools for phenotypic pre-screening in drug sensitivity assays: current research and future trends.

It is crucial to develop new antischistosomal drugs since there is no vaccine and the whole world is relying on only a single drug for the treatment of schistosomiasis. One of the obstacles to the development of drugs is the absence of the high throughput objective screening methods to assess drug compounds efficacy. Thus for identification of new drug compounds candidates, fast and accurate in vitro assays are unavoidable and more research efforts in the field of drug discovery can target schistosomula. This review presents a substantial overview of the present state of in vitro drug sensitivity assays developed so far for the determination of anti-schistosomula activity of drug compounds, natural products and derivatives using newly transformed schistosomula (NTS). It highlights some of the challenges involved in in vitro compound screening using NTS and the way forward.

Mycobacterium tuberculosis lineage 4 comprises globally distributed and geographically restricted sublineages.

Generalist and specialist species differ in the breadth of their ecological niches. Little is known about the niche width of obligate human pathogens. Here we analyzed a global collection of Mycobacterium tuberculosis lineage 4 clinical isolates, the most geographically widespread cause of human tuberculosis. We show that lineage 4 comprises globally distributed and geographically restricted sublineages, suggesting a distinction between generalists and specialists. Population genomic analyses showed that, whereas the majority of human T cell epitopes were conserved in all sublineages, the proportion of variable epitopes was higher in generalists. Our data further support a European origin for the most common generalist sublineage. Hence, the global success of lineage 4 reflects distinct strategies adopted by different sublineages and the influence of human migration.

Viral etiology of severe acute respiratory infections in hospitalized children in Cameroon, 2011-2013.

BACKGROUND: Severe acute respiratory illness (SARI) is recognized as an important cause of morbidity, mortality, and hospitalization among children in developing countries. Little is known, however, in tropical countries like Cameroon about the cause and seasonality of respiratory infections, especially in hospitalized settings. OBJECTIVES: Our study investigates the viral etiology and seasonality of SARI in hospitalized children in Yaounde, Cameroon. METHODS: Prospective clinic surveillance was conducted to identify hospitalized children aged ≤15 years presenting with respiratory symptoms ≤5-day duration. Demographic and clinical data, and respiratory specimens were collected. Nasopharyngeal samples were tested for 17 respiratory viruses using a multiplex polymerase chain reaction. The viral distribution and demographic data were statistically analyzed. RESULTS: From September 2011 through September 2013, 347 children aged ≤15 years were enrolled. At least one virus was identified in each of 65·4% children, of which 29·5% were coinfections; 27·3% were positive for human adenovirus (hAdV), 13·2% for human respiratory syncytial virus (hRSV), 11·5% for rhinovirus/enterovirus (RV/EV), 10·6% for human bocavirus (hBoV), 9·8% for influenza virus (Inf), 6·6% for human parainfluenza virus (hPIV), 5·7% for human coronavirus (hCoV), and 2·3% for human metapneumovirus (hMPV). While hRSV showed seasonal patterns, hAdV and RV/EV were detected throughout the year and no evident temporal patterns were observed for the remaining viruses. CONCLUSION: Respiratory viruses were associated with a high burden of hospitalizations among children in Cameroon. Nevertheless, additional studies evaluating asymptomatic Cameroonian children will be important in understanding the relationship between viral carriage and disease.

Strong decrease in streptomycin-resistance and absence of XDR 12 years after the Reorganization of the National Tuberculosis Control Program in the Central Region of Cameroon.

BACKGROUND: In the 1990s, resistance rates of 15% for streptomycin-resistance and 0.6% for multidrug-resistance (MDR) were reported from the Central Region of Cameroon. This work assesses drug resistant tuberculosis in this region 12 years after reorganization of the National Tuberculosis Control Program (NTCP). METHODS: This cross-sectional study was conducted from April 2010 to March 2011 in Jamot Hospital in Yaoundé, Cameroon. Only patients with smear positive pulmonary tuberculosis were included. Sputa were cultured and subsequently underwent drug susceptibility testing (DST). All consenting individuals were tested for their HIV status. RESULTS: A total of 665 smear positive pulmonary tuberculosis patients were enrolled. The HIV prevalence was 28.5% (95%CI [25.2-32.1]). Of the 582 sputa that grew Mycobacterium tuberculosis complex species, DST results were obtained for 576. The overall resistance rate was 10.9% (63/576). The overall resistance rates for single drug resistance were: isoniazid-resistance 4.7% (27/576), streptomycin-resistance 3.3% (19/576), rifampicin-resistance 0.2% (1/576), kanamycin-resistance 0.2% (1/576) and ofloxacin-resistance 0.2% (1/576). The MDR rate was 1.1% (6/576) and no extensively drug resistant tuberculosis (XDR) was detected. CONCLUSIONS: The data show that reorganization of the NTCP resulted in a strong decrease in streptomycin-resistance and suggest that it prevented the emergence of XDR in the Central Region of Cameroon.