Cervicovaginal Immune Activation in Zambian Women With Female Genital Schistosomiasis.

HIV-1 infection disproportionately affects women in sub-Saharan Africa, where areas of high HIV-1 prevalence and Schistosoma haematobium endemicity largely overlap. Female genital schistosomiasis (FGS), an inflammatory disease caused by S. haematobium egg deposition in the genital tract, has been associated with prevalent HIV-1 infection. Elevated levels of the chemokines MIP-1α (CCL-3), MIP-1ß (CCL-4), IP-10 (CXCL-10), and IL-8 (CXCL-8) in cervicovaginal lavage (CVL) have been associated with HIV-1 acquisition. We hypothesize that levels of cervicovaginal cytokines may be raised in FGS and could provide a causal mechanism for the association between FGS and HIV-1. In the cross-sectional BILHIV study, specimens were collected from 603 female participants who were aged 18-31 years, sexually active, not pregnant and participated in the HPTN 071 (PopART) HIV-1 prevention trial in Zambia. Participants self-collected urine, and vaginal and cervical swabs, while CVLs were clinically obtained. Microscopy and Schistosoma circulating anodic antigen (CAA) were performed on urine. Genital samples were examined for parasite-specific DNA by PCR. Women with FGS (n=28), defined as a positive Schistosoma PCR from any genital sample were frequency age-matched with 159 FGS negative (defined as negative Schistosoma PCR, urine CAA, urine microscopy, and colposcopy imaging) women. Participants with probable FGS (n=25) (defined as the presence of either urine CAA or microscopy in combination with one of four clinical findings suggestive of FGS on colposcope-obtained photographs) were also included, for a total sample size of 212. The concentrations of 17 soluble cytokines and chemokines were quantified by a multiplex bead-based immunoassay. There was no difference in the concentrations of cytokines or chemokines between participants with and without FGS. An exploratory analysis of those women with a higher FGS burden, defined by ≥2 genital specimens with detectable Schistosoma DNA (n=15) showed, after adjusting for potential confounders, a higher Th2 (IL-4, IL-5, and IL-13) and pro-inflammatory (IL-15) expression pattern in comparison to FGS negative women, with differences unlikely to be due to chance (p=0.037 for IL-4 and p<0.001 for IL-5 after adjusting for multiple testing). FGS may alter the female genital tract immune environment, but larger studies in areas of varying endemicity are needed to evaluate the association with HIV-1 vulnerability.

Prevalence and genotypic characterization of Giardia duodenalis isolates from asymptomatic school-going children in Lusaka, Zambia.

Giardia duodenalis is one of the most common causes of diarrhea in humans with about 250-300 million cases per year. It is considered to be a species complex comprising of eight genetic assemblages (A to H), with assemblages A and B being the major causes of human infections. In this study we carried out genotypic characterization of G. duodenalis isolates detected in asymptomatic school-going children aged 3-16 years. Between May and September 2017, a total of 329 fecal samples were collected from school-going children from Chawama compound of Lusaka City and were screened for Giardia by microscopic examination. All microscopically positive fecal samples were analyzed by semi-nested polymerase chain reaction (PCR) targeting the glutamate dehydrogenase (gdh) gene. Genotyping of amplified PCR products was conducted by restriction fragment length polymorphism (RFLP) and DNA sequence analysis. Microscopically, Giardia was found in 10% (33/329) of fecal samples. The PCR-RFLP analysis of the gdh gene revealed assemblages A and B in 27.3% (9/33) and 72.7% (24/33), respectively. Furthermore, analysis with restriction enzymes identified sub-assemblages AII (27.3%, 9/33), BIII (12.1%, 4/33), BIV (51.5%, 17/33) and mixed infections of BIII and BIV (9.1%, 3/33). Phylogenetic analysis showed the clustering of 27.6% (8/29) and 72.4% (21/29) of Zambian Giardia gdh gene sequences into assemblages A and B, respectively. This study has revealed the presence of both assemblage A and B and that spread of G. duodenalis in school-going children appears to be mostly through anthroponotic transmission. To our knowledge, this is the first report of genotypic characterization of G. duodenalis identified in Zambia.

Rapid sequencing-based diagnosis of infectious bacterial species from meningitis patients in Zambia.

OBJECTIVES: We have developed a portable system for the rapid determination of bacterial composition for the diagnosis of infectious diseases. Our system comprises of a nanopore technology-based sequencer, MinION, and two laptop computers. To examine the accuracy and time efficiency of our system, we provided a proof-of-concept for the detection of the causative bacteria of 11 meningitis patients in Zambia. METHODS: We extracted DNA from cerebrospinal fluid samples of each patient and amplified the 16S rRNA gene regions. The sequencing library was prepared, and the sequenced reads were simultaneously processed for bacterial composition determination using the minimap2 software and the representative prokaryote genomes. RESULTS: The sequencing results of four of the six culture-positive samples were consistent with those of conventional culture-based methods. The dominant bacterial species in each of these samples were identified from the sequencing data within only 3 min. Although the major bacterial species were also detected from the other two culture-positive samples and five culture-negative samples, their presence could not be confirmed. Moreover, as a whole, although the number of sequencing reads obtained within a short sequencing run was small, there was no change in the major bacterial species over time with prolonged sequencing. In addition, the processing time strongly correlated with the number of sequencing reads used for the analysis. CONCLUSION: Our results suggest that time-effective analysis could be achieved by determining the number of sequencing reads required for the rapid diagnosis of infectious bacterial species depending on the complexity of bacterial species in a sample.

Low IL-6, IL-10, and TNF-α and High IL-13 Cytokine Levels Are Associated with Severe Hepatic Fibrosis in Schistosoma mansoni Chronically Exposed Individuals.

Several studies have attributed the etiopathogenesis of chronic Schistosoma mansoni related hepatic fibrosis to unregulated immune responses against trapped parasite ova in the host. However, there is limited data on immune profiles associated with varying degrees of the disease in a population under chronic exposure to the parasite. We therefore investigated the role of selected T-helper (Th)1, Th2, and Th17 cytokines in relation to hepatic fibrosis severity among individuals resident in a hyper-Schistosoma mansoni endemic region of Western Zambia. Two hundred and forty-four S. mansoni infected individuals with and without fibrosis were analysed for cytokine profiles. Based on hepatic fibrosis stage as determined by ultrasound, participants were categorized into Group 0, Group I, Group II, and Group III. Cytokines were measured in S. mansoni egg stimulated whole blood culture supernatants using the BD Cytometric Bead Array kits. Compared to the nonfibrotic group, participants in the severe hepatic fibrotic group produced less interleukin- (IL-) 6, IL-10, and tumour necrosis factor-alpha (TNF-α). On the other hand, IL-13 was significantly elevated in this group compared to the nonfibrotic group (p < 0.001). Our results suggest that low IL-6, IL-10, and TNF-α and high IL-13 levels may influence S. mansoni disease progression.

A case report: primary amoebic meningoencephalitis in a young Zambian adult.

BACKGROUND: Primary amoebic meningoencephalitis (PAM) is a fulminant disease of the brain caused by Naegleria fowleri. Although the disease is rare, the case fatality rate is very high. In this report, we describe the first case of PAM in Zambia. CASE PRESENTATION: The patient presented with sudden onset of seizures and fever on admission. On physical examination he was febrile, comatose and with a stiff neck. Cerebral spinal fluid (CSF) collected on admission did not reveal any organism on microscopy or culture but showed elevated white cell count. A working diagnosis of severe septicemia with acute meningoencephalitis was then made and the patient was started on IV Cephtriaxone (2 g) twice daily. Despite receiving treatment, his condition deteriorated. A second CSF sample collected on day 3 was also negative for bacteria and other organisms. However, a repeat CSF sample collected on day 8 revealed numerous motile organisms that were identified as Naegleria on microscopy and confirmed to be N. fowleri on polymerase chain reaction. The patient died on day 8 of hospital admission after having received one dose of Amphotericin B (50 mg). Features consistent with PAM were detected on autopsy. CONCLUSION: The isolation of N. fowleri in this patient calls for increased awareness among clinical and laboratory staff on suspected PAM cases to promptly diagnose and effectively manage the disease.

High Schistosoma mansoni disease burden in a rural district of western Zambia.

Schistosoma mansoni disease is endemic in most parts of rural Zambia, and associated complications are common. We conducted a cross-sectional study among 754 people in rural communities of Kaoma District, western Zambia to determine the burden of S. mansoni infection and associated morbidity. Parasitology and ultrasonography assessments were conducted on consenting participants. The overall prevalence of S. mansoni infection and geometric mean egg count (GMEC) were 42.4% (304) and 86.6 eggs per gram (95% confidence interval = 75.6-99.6), respectively. Prevalence was highest in the age group of 15-19 years old (adjusted prevalence ratio = 1.70, P = 0.017). S. mansoni-related portal fibrosis was detected in 26% of the participants screened. Participants above 39 years old were 2.93 times more likely to have fibrosis than the 7-9 years old age group (P = 0.004). The study highlights the high burden of S. mansoni disease in this area and calls for immediate interventions to avert complications associated with the disease.

Diagnosis of Schistosoma mansoni without the stool: comparison of three diagnostic tests to detect Schistosoma [corrected] mansoni infection from filtered urine in Zambia.

Diagnosis for intestinal Schistosoma mansoni lacks sensitivity and is arduous to conduct. The standard diagnostic tests, Kato-Katz (KK) and circulating cathodic antigen (CCA) both lack sensitivity and with KK, require obtaining, transporting, and examining fresh stool. We compared diagnostic efficacy of KK, CCA, and polymerase chain reaction (PCR) to detect S. mansoni infection (species-specific DNA) from 89 filtered urine samples collected in Zambia. The PCR was the strongest indicator of positive cases with sensitivity and specificity of 100% in comparison to CCA (67% and 60%) and KK (50% and 100%). High positive and negative predictive values (100%) were also indicative of robustness of PCR. The same pattern was observed when stratified for sex and age group-specific analysis. Diagnosis of S. mansoni from filtered urine samples by PCR is an effective means to detect low intensity infection and would enhance the effectiveness of surveillance and control programs of schistosomiasis.