Performance evaluation of malaria microscopists working at rechecking laboratories in Ethiopia

BACKGROUND

Microscopic diagnosis of Giemsa-stained thick and thin blood films has remained the standard laboratory method for diagnosing malaria. High quality performance of microscopists that examine blood slides in health facilities remains critically important.

MATERIALS AND METHODS

A cross-sectional study was conducted to assess the performance of 107 malaria microscopists working at 23 malaria rechecking laboratories in Ethiopia. A set of 12 blood film slides was distributed to each microscopist. Data was collected and exported to SPSS version 20 for analysis. Chi-square, sensitivity, specificity, percent agreement, and kappa scores were calculated to assess performance in detecting and identification of Plasmodium species.

RESULTS

The mean age of the participants was 30 ± 5 yrs and most of them (54; 50.5%) were working at regional reference laboratories. Overall, the sensitivity of participants in detecting and identifying malaria parasite species was 96.8% and 56.7%, respectively. The overall agreement on detection and identification of malaria species was 96.8% (Kappa = 0.9) and 64.8% (Kappa = 0.33), respectively. The least accurately identified malaria parasite species was P. malariae (3/107; 2.8%) followed by P. ovale (35/107; 32.7%). Participants working at hospital laboratories had the highest percentage (72.3 %, Kappa=0.51) of accurate species identification. Study participants that had participated in malaria microscopy and quality assurance trainings were significantly better at quantifying parasite densities (P<0.001).

CONCLUSION

The accuracy of parasite identification and quantification differed strongly between participants and expert microscopists. Therefore, regular competency assessment and training for malaria microscopists should be mandatory to assure proper diagnosis and management of malaria in Ethiopia.

Asymptomatic Helminth Infection in Active Tuberculosis Is Associated with Increased Regulatory and Th-2 Responses and a Lower Sputum Smear Positivity

Background

The impact of intestinal helminth infection on the clinical presentation and immune response during active tuberculosis (TB) infection is not well characterized. Our aim was to investigate whether asymptomatic intestinal helminth infection alters the clinical signs and symptoms as well as the cell mediated immune responses in patients with active TB.

Methodology

Consecutive, newly diagnosed TB patients and healthy community controls (CCs) were recruited in North-west Ethiopia. TB-score, body mass index and stool samples were analyzed. Cells from HIV-negative TB patients (HIV-/TB) and from CCs were analyzed for regulatory T-cells (Tregs) and cytokine responses using flow cytometry and ELISPOT, respectively.

Results

A significantly higher ratio of helminth co-infection was observed in TB patients without HIV (Helm+/HIV-/TB) compared to HIV negative CCs, (40% (121/306) versus 28% (85/306), p = 0.003). Helm+/HIV-/TB patients showed significantly increased IL-5 secreting cells compared to Helm-/HIV-/TB (37 SFU (IQR:13–103) versus 2 SFU (1–50); p = 0.02, n = 30). Likewise, levels of absolute Tregs (9.4 (3.2–16.7) cells/μl versus 2.4 (1.1–4.0) cells/μl; p = 0.041) and IL-10 secreting cells (65 SFU (7–196) versus 1 SFU (0–31); p = 0.014) were significantly higher in Helm+/HIV-/TB patients compared to Helm-/HIV-/TB patients. In a multivariate analysis, a lower rate of sputum smear positivity for acid fast bacilli, lower body temperature, and eosinophilia were independently associated with helminth infection in TB patients.

Conclusions

Asymptomatic helminth infection is associated with increased regulatory T-cell and Th2-type responses and a lower rate of sputum smear positivity. Further studies are warranted to investigate the clinical and immunological impact of helminth infection in TB patients.

The effects of helminth infection on chronic infectious diseases such as tuberculosis (TB) merit further characterization. There is limited data regarding the impact of helminth co-infection on clinical and immunological outcomes of TB from clinical field studies in high endemic areas. We tried to address some of these issues in a randomized clinical trial in order to investigate the impact of albendazole treatment on helminth co-infected TB patients. In the present study we focused on the clinical and immunological effects of helminth infection on TB. We found that concomitant asymptomatic helminth infection profoundly affects the immune phenotype of TB patients with a strong leaning towards Th2 types of immune response such as increased regulatory T cells as well as IL-5 and IL-10 secreting cells. Furthermore, helminth co-infection was associated with a significantly lower ratio of sputum smear positivity which correlated to the egg load in helminth positive TB patients. Whether the effect of helminth infection may have an impact on the diagnosis and treatment of active TB remains to be further investigated.

Genetic diversity of Plasmodium falciparum isolates based on MSP-1 and MSP-2 genes from Kolla-Shele area, Arbaminch Zuria District, southwest Ethiopia

BACKGROUND

The genetic diversity of Plasmodium falciparum has been extensively studied in various countries. However, limited data are available from Ethiopia. This study was conducted to evaluate the extent of genetic diversity of P. falciparum in Kolla-Shele, in the southwest of Ethiopia.

METHODS

A total of 88 isolates from patients with uncomplicated P. falciparum attending Kolla-Shele Health Centre was collected from September to December, 2008. After extraction of DNA by Chelex method, the samples were genotyped by using nested-PCR of msp1 (block 2) and msp2 (block 3) including their allelic families: K1, MAD20, RO33 and FC27, 3D7/IC1, respectively.

RESULTS

Allelic variation in both msp1 and msp2 were identified in the 88 blood samples. For msp1 67% (59/88) and msp2 44% (39/88) were observed. K1 was the predominant msp1 allelic family observed in 33.9% (20/59) of the samples followed by RO33 and MAD20. Of the msp2 allelic family 3D7/IC1 showed higher frequency (21.5%) compared to FC27 (10.3%). A total of twenty-three alleles were detected; of which, eleven were from msp2 and twelve from msp2 genes. Fifty-nine percent of isolates had multiple genotypes and the overall mean multiplicity of infection was 1.8 (95% CI: 1.48-2.04). The heterozygosity index was 0.79 and 0.54for msp1 and msp2, respectively. There was no statically significant difference in the multiplicity of infection by either age or parasite density (P > 0.05).

CONCLUSION

This genetic diversity study showed the presence of five allelic types in the study area, with dominance K1 in the msp1 family and 3D7/IC1 in the msp2 family. Multiple infections were observed in nearly 60% of the samples.

Physicochemical and sensory evaluation of some cooking banana (Musa spp.) for boiling and frying process

Experiments were conducted to study physicochemical properties of four cooking banana varieties (Cardaba, Nijiru, Matoke and Kitawira) and to determine their suitability for chips processing and boiling quality. A randomized complete block design with three replications was employed. Pulp to peel ratio, pulp firmness (before and after), total soluble solids, pH, titratable acidity, ascorbic acid, ease of peeling, pulp water absorption, duration of cooking (or boiling) and dry matter are the most important parameters to evaluate the quality of cooking banana including plantain. The different variety affected the fruit physical characteristics significantly (P ≤ 0.05). The Cardaba varieties fruit was found to be the heaviest and the longest. The Kitawira and Nijiru varieties had the smallest, shortest and thinnest fruit. The Cardaba contained 88 % more edible portions per unit fresh weight than the peel. The Nijiru, Matoke and Kitawira contained more pulp weight than peel weight. Most fruit chemical quality parameters were significantly (P ≤ 0.05) affected by the varieties. Similarly, the boiling and chips qualities were significantly (P ≤ 0.05) affected by varieties. Among others, the Cardaba variety was found to have high fruit weight, fruit length, fruit girth, fruit volume, total soluble solids, ascorbic acid, dry matter and low total titratable acidity. Thus, Cardaba provided the best quality boiled pulp which can serve for diversified culinary purposes. Generally, the Nijiru, Kitawira and Matoke varieties were found to be superior to produce acceptable quality chips. These varieties are recommended for chips development by food processors in Ethiopia.

The impact of asymptomatic helminth co-infection in patients with newly diagnosed tuberculosis in north-west Ethiopia

BACKGROUND

Areas endemic of helminth infection, tuberculosis (TB) and HIV are to a large extent overlapping. The aim of this study was to assess the impact of asymptomatic helminth infection on the immunological response among TB patients with and without HIV, their house hold contacts and community controls.

METHODOLOGY

Consecutive smear positive TB patients (n = 112), their household contacts (n = 71) and community controls (n = 112) were recruited in Gondar town, Ethiopia. Stool microscopy, HIV serology, serum IgE level, eosinophil and CD4 counts were performed and tuberculosis patients were followed up for 3 months after initiation of anti-TB treatment.

RESULTS

Helminth co-infection rate was 29% in TB patients and 21% in both community control and household contacts (p = 0.3) where Ascaris lumbricoides was the most prevalent parasite. In TB patients the seroprevalence of HIV was 47% (53/112). Eosinophilia and elevated IgE level were significantly associated with asymptomatic helminth infection. During TB treatment, the worm infection rate of HIV+/TB patients declined from 31% (10/32) at week 0 to 9% (3/32) at week 2 of TB treatment, whereas HIV-/TB patients showed no change from baseline to week 2, 29% (13/45) vs. 22.2% (10/45). This trend was stable at week 8 and 12 as well.

CONCLUSION

One third of smear positive TB patients were infected with helminths. Eosinophilia and elevated IgE level correlated with asymptomatic worm infection, indicating an effect on host immunity. The rate of worm infection declined during TB treatment in HIV+/TB co-infected patients whereas no decline was seen in HIV-/TB group.