BACKGROUND: This study assessed seroprevalence of poliovirus antibodies in children from selected poliovirus high-risk areas of the Far North region of Cameroon which serves to monitor polio immunization program. METHODS: This was a community-based cross-sectional seroprevalence survey involving collection of dried blood specimens (DBS) among children aged 12-59months (n=401). Multi-stage cluster sampling using GIS was applied to select the study sample. Collected DBS were analysed with microneutralization assays for poliovirus neutralizing antibody levels. RESULTS: The overall seroprevalence of types 1, 2 and 3 neutralizing antibodies were 86.8% (95% confidence interval [CI]: 83.1-89.8), 74.6% (95% CI: 70.1-78.6) and 79.3% (95% CI: 75.1-83.0), respectively. Median titers (log(2) scale) for type 1, 2 and 3 were 7.17 (6.5-7.5), 5.17 (4.83-5.5), and 6.17 (5.5-6.5), respectively. There was an increasing trend in median titers and seroprevalence with age, statistically significant between the youngest and oldest age groups (p<0.001). CONCLUSION: Though there were several opportunities for vaccination through supplementary immunization activities (SIA) and routine immunization (RI), seroprevalence levels were low for all three serotypes, particularly for type 2. This highlights the need to strengthen RI and SIA quality coverage. Low population immunity makes Cameroon vulnerable to new importations and spread of polioviruses.

Melioidosis is caused by Burkholderia pseudomallei and is predominantly seen in tropical regions. The clinical signs and symptoms of the disease are non-specific often resulting in misdiagnosis, failure of treatment, and poor clinical outcome. Septicemia with septic shock is the most common cause of death with mortality rates above 40%. Bacterial culture is the gold standard for diagnosis but it has low sensitivity and takes days to produce definitive results. Early laboratory diagnosis can help guide physicians to provide treatment specific to B. pseudomallei In our study, we adapted host gene expression signatures obtained from microarray data of B. pseudomallei infected cases to develop a real-time PCR diagnostic test using two differentially expressed genes, AIM2 (Absent in Melanoma 2) and FAM26F (Family with sequence similarity 26, member F). We tested blood from 33 patients with B. pseudomallei and 29 patients with other bacterial infections to validate the test and determine cutoff values for use in a cascading diagnostic algorithm. Differentiation of septicemic melioidosis from other sepsis cases had a sensitivity of 82%, specificity of 93%, and negative and positive predictive values (NPV and PPV) of 82% and 93% respectively. Separation of cases likely to be melioidosis from unlikely cases in non-bacteremic situations showed a sensitivity of 40%, specificity of 54%, and NPV and PPV of 44% and 50% respectively. We suggest that our AIM2 and FAM26F expression combination algorithm could be beneficial for early melioidosis diagnosis offering a result within 24 hours of admission.

The genetic characterization of measles viruses is an important tool for measles surveillance. Reverse cold chain requirements for the transportation of samples to reference laboratories are challenging in resource-limited settings. FTA(R) cards facilitate transport of virologic samples at ambient temperature as non-infectious material; however, the utility of FTA(R) cards for detection and genotyping of measles virus from clinical samples had not been evaluated. Throat swabs (TS) and oral fluid (OF) samples were collected from suspected measles cases in the Democratic Republic of the Congo. Virus detection (RT-qPCR) and genotyping (end-point RT-PCR) were compared for samples from 238 suspected cases; these samples were either transported using the reverse cold chain or at ambient temperature on FTA(R) cards. Virus detection showed excellent positive agreement for OF compared to TS (95.3%, CI [91.6, 97.4]), in contrast to 79.4% (CI 73.5, 84.3) for TS on FTA, and 85.5% (CI 80.2, 89.6) for OF on FTA compared to OF. Genotyping results obtained for a subset of samples indicated that 77.3% of all TS and 71.0% of OF would produce genotype information compared to 41.6% of TS and 41.3% of OF on FTA(R) cards. Similar results were found for 16 measles-negative samples that were confirmed as rubella cases. Measles genotype B3 and rubella genotype 2B were detected. FTA(R) cards have limited utility for virologic surveillance of sporadic cases of measles; however, they can be a useful tool for the expansion of virologic surveillance in countries where the reverse cold chain is not available.

BACKGROUND: Diphtheria is a vaccine-preventable disease. When vaccination coverage and population immunity are low, outbreaks can occur. We investigated a diphtheria outbreak in Lao People's Democratic Republic that occurred during 2012-2013 and highlighted challenges in immunization services delivery to children in the country. METHODS: We reviewed diphtheria surveillance data from April 1, 2012-May 31, 2013. A diphtheria case was defined as a respiratory illness consisting of pharyngitis, tonsillitis, or laryngitis, and an adherent tonsillar or nasopharyngeal pseudomembrane. To identify potential risk factors for diphtheria, we conducted a retrospective case-control study with two aged-matched neighborhood controls per case-patient in Houaphan Province, using bivariate analysis to calculate matched odds ratio (mOR) with 95% confidence intervals (CI). Reasons for non-vaccination among unvaccinated persons were assessed. RESULTS: Sixty-two clinical cases of diphtheria and 12 diphtheria-related deaths were reported in seven of 17 provinces. Among case-patients, 43 (69%) were <15years old, five (8%) reported receiving three DTP doses (DTP3), 21 (34%) had received no DTP doses, and 35 (56%) had unknown vaccination status. For the case-control study, 42 of 52 diphtheria case-patients from Houaphan province and 79 matched-controls were enrolled. Five (12%) case-patients and 20 (25%) controls had received DTP3 (mOR=0.4, CI=0.1-1.7). No diphtheria toxoid-containing vaccine was received by 20 (48%) case-patients and 38 (46%) controls. Among case-patients and controls with no DTP dose, 43% of case-patients and 40% of controls lacked access to routine immunization services. CONCLUSION: Suboptimal DTP3 coverage likely caused the outbreak. To prevent continued outbreaks, access to routine immunization services should be strengthened, outreach visits need to be increased, and missed opportunities need to be minimized. In the short term, to rapidly increase population immunity, three rounds of DTP immunization campaign should be completed, targeting children aged 0-14years in affected provinces.

There are few multilaboratory studies on antifungal combinations testing to suggest a format for use in clinical laboratories. In the present study, eight laboratories tested quality control (QC) strain Candida parapsilosis ATCC 22019 and clinical isolates Candida albicans 20533.043, C. albicans 20464.007, Candida glabrata 20205.075, and C. parapsilosis 20580.070. The clinical isolates had relatively high azole and echinocandin MICs. A modified CLSI M-27A3 protocol was used, with 96-well custom-made plates containing checkerboard pair-wise combinations of amphotericin B (AMB), anidulafungin (AND), caspofungin (CSP), micafungin (MFC), posaconazole (PSC), and voriconazole (VRC). The end points were scored visually and on a spectrophotometer or ELISA reader for 50% growth reduction (IC50). Combination IC50 were used to calculate summation FICIs (SigmaFIC, fractional inhibitory concentration indices) based on the Lowe additivity formula. Results revealed that IC50 values of all drug combinations were lower or equal to the IC50 of individual drugs in the combination. A majority of the SigmaFIC values were indifferent (SigmaFIC = 0.51 -2.0), but no antagonism was observed (SigmaFIC ≥ 4). Synergistic combinations (SigmaFIC ≤ 0.5) were found from both visual and spectrophotometric readings for AMB-PSC against C. glabrata and for AMB-AND and AMB-CSP against C. parapsilosis. Additional synergistic interactions were revealed by either of the two end points for AMB-AND, AMB-CSP, AMB-MCF, AMB-PSC, AMB-VRC, AND-PSC, CSP-MCF, and CSP-PSC. The percent agreements among participating laboratories ranged from 37.5 % (lowest) for AND-CAS and POS-VOR and 87.5% (highest) for AB-MF and AND-CAS. Median SigmaFIC values showed wide dispersion, and inter-laboratory agreements were less than 85% in most instances. Additional studies are needed to improve inter-laboratory reproducibility of antifungal combination testing.