Chitungwiza Municipality

In anticipation of rotavirus vaccine introduction, the Zimbabwe Ministry of Health initiated rotavirus surveillance in 2008 to describe the rotavirus epidemiological trends and circulating genotypes among children <5 years of age. Active hospital-based surveillance for diarrhea was conducted at 3 sentinel sites from January 2008 to December 2011. Children aged <5 years, who presented with acute gastroenteritis as a primary illness and who were admitted to a hospital ward or treated at the emergency unit, were enrolled in the surveillance program and had a stool specimen collected and tested for rotavirus by enzyme immunoassay. Genotyping of a sample of positive specimens was performed using reverse-transcription polymerase chain reaction. A total of 3728 faecal samples were collected and tested during the 4 year surveillance period and 1804 (48.5%) tested rotavirus positive. The highest prevalence of rotavirus diarrhea was found during the dry, cool season. Rotavirus positivity peaked in children 3-17 months of age with almost 80% of cases. Compared with rotavirus-negative cases, rotavirus-positive cases were more likely to be dehydrated (26% vs. 14%, P ≤ 0.001) and have vomiting (77% vs. 57%, P ≤ 0.001) and less likely to have fever (17% vs. 24%, P = 0.03). G9P[8] (43.3%), G1P[8] (11.8%), G2P[4] (8.7%), G2P[6] (8.7%) and G12P[6] (8.7%) were the most common genotypes detected. Rotavirus causes a significant disease burden among children <5 years of age in Zimbabwe. This active surveillance system can serve as a platform to monitor the impact of rotavirus vaccine on disease burden following vaccine introduction.

BackgroundThe World Health Organization (WHO)'s "3 × 5 program" has spurred efforts to place 3 million people on combination antiretroviral therapy (ART) for treatment of AIDS in resource-limited countries. Paradoxically, the cost of CD4+ T-lymphocyte count essential for decision-making to commence HIV positive adults on ART as well as for monitoring responses to ART remains unaffordable in most resource-limited countries. Thus, low-cost methods for enumerating CD4+ T-lymphocyte are urgently needed.ObjectiveTo evaluate Cyflow cytometry (Cyflow SL, Partec, Munster, Germany) for enumeration of absolute CD4+ T-lymphocyte in subtype C HIV-1 seropositive subjects using FACSCount (Becton and Dickinson, Immunocytometry Systems, San Jose, CA, USA) as the "predicate method".MethodsA total of 150 HIV-1 seropositive subjects were included in the evaluation exercise. Fifty-eight specimens were collected from pregnant HIV-1 seropositive women (subtype C drug resistance study). Twenty-seven specimens were collected from women and their spouses with AIDS followed in a Duke ART study to assess the immunologic and virologic responses to generic ART, comprising Stavudine, Lamivudine and Nevirapine (Stalanev, Varichem Labs, Harare, Zimbabwe). Sixty-five specimens were collected from AIDS patients enrolled in an ongoing Kaposi Sarcoma (KS) study to investigate impact of ART on KS progression. Enumeration of CD4+ T-lymphocytes using FACSCount is routinely conducted for all the three studies. The Medical Research Council of Zimbabwe and Medicines Control Authority of Zimbabwe approved the studies. Whole blood was collected in EDTA vacutainer tubes and aliquoted into two tubes (200 μL in each). CD4+ T-lymphocyte counts were enumerated using a Cyflow counter, in the Department of Immunology and a FACSCount in the Department of Obstetrics and Gynaecology within 6 hours of phlebotomy following manufacturers' instructions.ResultsUsing linear regression analysis, there was a very strong correlation (R = 0.991) between the overall CD4+ T-lymphocyte counts obtained by FACSCount and those obtained by Cyflow. When data analysis was stratified by study groups, there was a strong correlation between the FACSCount and Cyflow CD4+ T-lymphocyte counts from subjects in the three independent studies; Subtype C resistance (R2 = 0.987), Duke ART (R2 = 0.980) and KS (R2 = 0.994), Table 1.Using Bland-Altman plots, the overall, absolute CD4+ T lymphocytes obtained by the two methods were in excellent agreement (mean difference 1.21, 95% Confidence Interval {CI): -2.1 to 3.3). For the 0–250 CD4+ T-lymphocytes range, the CD4 counts obtained using FACSCount were also in good agreement with those obtained using Cyflow counter (mean difference = 2.6 cells/μL, 95% CI: -1.1 to 6.3). Similarly, in the 251–500 (mean difference 1.0, cells/μL, 95% CI: -3.7 to 5.6) and the 501–1200 (mean difference = 0.29 cells/μL, 95% CI: -8.1 to 8.7) CD4 T-lymphocytes range, good agreement was observed.ConclusionThe Cyflow counter is as accurate as the FACSCount in enumerating absolute CD4+ T-lymphocytes in the range 1–1200 cells/μL. Cyflow cytometry is relatively affordable, easy to use technology that is useful not only in identifying HIV seropositive individuals who require ART but also for monitoring immunologic responses to ART.