Pathogenesis, diagnostic challenges and treatment of zika virus disease in resource-limited settings.

The association of Zika virus (ZIKV) infection with congenital malformation and neurological sequelae has brought significant global concern. Consequently, the World Health Organization (WHO) declared it "a public health emergency of International concern" on 1 February, 2016. A critical review of its pathogenesis would lead to a better understanding of the clinical features and the neurological complications. This review is based on literature search in PubMed/Medline, Google Scholar and the WHO, http://www.who.int. This include all relevant articles written in English published through June 2018, with subject heading and keywords such as Zika, ZIKV, Zika pathogenesis, diagnosis of Zika, Zika Nigeria, Zika Africa and Zika resource-limited settings. Following ZIKV infection, viraemia ensues targeting primarily the monocytes for both the Asian and African strains. ZIKV infection by an African strain appears to be more pathogenic, in early pregnancy tends to result in spontaneous abortion. Whereas an Asian strain tends to be less pathogenic and more chronic, this allows the pregnancy to continue, ultimately resulting in congenital malformations. There is no routine laboratory diagnosis of ZIKV infection in resource-constrained countries. Serologic tests should be interpreted with caution since there can be cross-reactivity with other flaviviruses, especially in Africa where the burden of infection with flaviviruses is comparatively high. There is a paucity of well-equipped laboratories for comprehensive ZIKV diagnosis. It is imperative to strengthen the health systems, improve health workforce and diagnostic capacity of such settings.

Diagnostic accuracy of Xpert MTB/RIF Ultra for childhood tuberculosis in West Africa - a multicenter pragmatic study.

OBJECTIVE: To evaluate the performance of Xpert Mycobacterium Tuberculosis/rifampicin (MTB/RIF) Ultra (Ultra) for diagnosis of childhood tuberculosis (TB) within public health systems. METHODS: In this cross-sectional study, children aged <15 years with presumptive pulmonary TB were consecutively recruited and evaluated for TB at tertiary-level hospitals in Benin, Mali, and Ghana. Bivariate random-effects models were used to determine the pooled sensitivity and specificity of Ultra against culture. We also estimated its diagnostic yield against a composite microbiological reference standard (cMRS) of positive culture or Ultra. RESULTS: Overall, 193 children were included in the analyses with a median (interquartile range) age of 4.0 (1.1-9.2) years, 88 (45.6%) were female, and 36 (18.7%) were HIV-positive. Thirty-one (16.1%) children had confirmed TB, 39 (20.2%) had unconfirmed TB, and 123 (63.7%) had unlikely TB. The pooled sensitivity and specificity of Ultra verified by culture were 55.0% (95% confidence interval [CI]: 28.0-79.0%) and 95.0% (95% CI: 88.0-98.0%), respectively. Against the cMRS, the diagnostic yield of Ultra and culture were 67.7% (95% CI: 48.6-83.3%) and 70.9% (95% CI: 51.9-85.8%), respectively. CONCLUSION: Ultra has suboptimal sensitivity in children with TB that were investigated under routine conditions in tertiary-level hospitals in three West African countries.

Improving the diagnosis of pulmonary tuberculosis using line probe assay and determining the factors associated with the disease in children in Jos, Nigeria.

INTRODUCTION: Diagnosing tuberculosis (TB), including pulmonary tuberculosis (PTB), in children remains a challenge, partly due to its paucibacillary nature in young children. Data on the use of line probe assay (LPA), on gastric and sputum samples, for diagnosing PTB in children are scarce. We determined the proportion of samples positive for Mycobacterium tuberculosis (MTB) by smear microscopy (SM) and LPA in presumptive PTB cases as well as the factors associated with PTB confirmed by LPA, in children in Jos, Nigeria. METHODS: An observational study in children aged 6 months-16 years. Gastric and sputum samples were examined by SM and by LPA for MTB using GenoType MTBDRplus Ver 2.0 (Hain Lifescience). Multivariate logistic regression was performed to determine the factors associated with PTB. RESULTS: Out of 103 children with presumptive PTB, 47 had confirmed PTB, 26 unconfirmed PTB and 30 unlikely PTB by LPA. In 67 gastric samples, MTB was identified by SM in 2 (3.0%) compared to 28 (41.8%) by LPA while in 31 sputum samples, MTB was identified by SM in 5 (16.1%) compared to 18 (58.1%) by LPA. The factors associated with pulmonary tuberculosis were an abnormal chest X-ray (adjusted odds ratio (AOR))=12.39 [3.75-40.90], p<0.001), sleeping in the same room with more than three persons (AOR=3.30 [1.23-8.85], p=0.018) and sleeping in a room with none or one window (AOR=2.86 [1.03-7.95], p=0.044). CONCLUSIONS: Line probe assay improves the diagnosis of pulmonary TB in children, especially with gastric samples, while an abnormal chest X-ray is a useful adjunct in PTB diagnosis. Avoiding overcrowding and having windows in sleeping rooms are a necessary part of TB prevention.

Low Zika virus seroprevalence among pregnant women in North Central Nigeria, 2016.

BACKGROUND: Zika virus (ZIKV) has been known for decades in Africa but contemporary data is lacking at large. OBJECTIVES: To describe the seroepidemiology of ZIKV in North Central Nigeria. STUDY DESIGN: We performed a cross-sectional study at six health care facilities in North Central Nigeria from January to December 2016. Detection of ZIKV antibodies was done using an anti-ZIKV recombinant non-structural protein 1 (NS1)-based ELISA. A colorimetric assay to detect ZIKV neutralizing antibodies was used on ELISA reactive and randomly selected ELISA non-reactive samples. ZIKV real-time RT-PCR was done on a subset of samples. RESULTS: A total of 468 individual samples were included with almost 60% from pregnant women. Using NS1-based ELISA, an anti-ZIKV positive rate of 6% for IgM and 4% for IgG was found. Pregnant women showed anti-ZIKV positive rates of 4% for IgM and 3% for IgG. None of the ZIKV antibody positive samples tested ZIKV RT-PCR positive. An association with male sex was found for anti-ZIKV IgG ELISA positivity (prevalence ratio 3.49; 95% confidence interval: 1.48-8.25; p = .004). No association with pregnancy, yellow fever vaccination or malaria was found for anti-ZIKV IgM or IgG positivity. ZIKV neutralizing antibodies were detected in 17/18 (94%) anti-ZIKV NS1 positive/borderline samples and in one sample without detectable ZIKV NS1 antibodies. Partial ZIKV E gene sequence was retrieved in one sample without ZIKV antibodies, which clustered within the West African ZIKV lineage. CONCLUSIONS: Our results show a largely ZIKV immunologically naïve population and reinforce the importance of ZIKV surveillance in Africa.