Erratum to: Development of novel multiplex microsatellite polymerase chain reactions to enable high-throughput population genetic studies of Schistosoma haematobium.

Unfortunately, the original version of this article [1], contained a mistake. In Table 1, the primers for Sh6 and Sh9 were included incorrectly. Instead of GGGATGTATGCAGACTTG TTGTTTGGCTGCAGTAAC and GCTGAGCTTGAGATTG CTTCTGTCCCATCGATACC they should have been Sh6 Forward Primer GGTGGATTACGCAATAG, Sh6 Reverse Primer TTTAATCAACCGGGTGTC and Sh9 Forward Primer GGGATGTATGCAGACTTG, Sh9 Reverse Primer TTGTTTGGCTGCAGTAAC respectively. A corrected version of Table 1 is included below

Development of novel multiplex microsatellite polymerase chain reactions to enable high-throughput population genetic studies of Schistosoma haematobium.

BACKGROUND: Human urogenital schistosomiasis caused by Schistosoma haematobium is widely distributed across Africa and is increasingly targeted for control and regional elimination. The development of new high-throughput, cost-effective molecular tools and approaches are needed to monitor and evaluate the impact of control programs on the parasite populations. Microsatellite loci are genetic markers that can be used to investigate how parasite populations change over time and in relation to external influences such as control interventions. FINDINGS: Here, 18 existing S. haematobium microsatellite loci were optimised to enable simultaneous amplification across two novel multiplex microsatellite PCR's, each containing nine loci. Methods were developed for the cost effective and rapid processing and microsatellite analysis of S. haematobium larval stages stored on Whatman-FTA cards and proved robust on miracidia and cercariae collected from Zanzibar and Niger. CONCLUSION: The development of these novel and robust multiplex microsatellite assays, in combination with an improved protocol to elute gDNA from Whatman-FTA fixed schistosome larval stages, enables the high-throughput population genetic analysis of S. haematobium. The molecular resources and protocols described here advance the way researchers can perform multi locus-based population genetic analyses of S. haematobium as part of the evaluation and monitoring of schistosomiasis control programmes.

Comparison of the Kato-Katz method and ether-concentration technique for the diagnosis of soil-transmitted helminth infections in the framework of a randomised controlled trial.

Soil-transmitted helminth infections are a major public health problem. An accurate diagnosis is important in order to identify individuals and communities in need of intervention, and for monitoring drug efficacy and potential emergence of resistance. We compared the accuracy of the Kato-Katz method and ether-concentration technique for the diagnosis of soil-transmitted helminth infections within a randomised controlled trial. Quadruplicate Kato-Katz thick smears (duplicate Kato-Katz from two stool samples each) were examined before (baseline) and 3 weeks after treatment (follow-up). Additionally, at baseline and follow-up, the first stool sample was subjected to an ether-concentration method. We determined the prevalence, sensitivity, negative predictive value, diagnostic agreement and cure rates for single and duplicate Kato-Katz thick smears from the first stool sample, quadruplicate Kato-Katz thick smears produced from two stool samples and single ether-concentration as compared to our 'gold' standard (i.e. quadruplicate Kato-Katz plus ether-concentration). Quadruplicate Kato-Katz revealed a higher sensitivity than single ether-concentration for Trichuris trichiura at baseline (94.3 % vs. 88.5 %, p = 0.002) and follow-up (93.8 % vs. 83.5 %, p < 0.001). In contrary, at follow-up, ether-concentration showed a higher sensitivity than quadruplicate Kato-Katz for Ascaris lumbricoides diagnosis (86.7 % vs. 46.7 %, p = 0.012). The ether-concentration method showed similar or slightly higher sensitivity than the Kato-Katz technique based on a single stool sample for all soil-transmitted helminth infections. The estimated cure rates were heavily dependent on the diagnostic technique and sampling effort. In conclusion, data on the prevalence of soil-transmitted helminth infections and the efficacy of anthelminthics are greatly influenced by the diagnostic method and sampling effort. The ether-concentration technique is a valuable alternative to the Kato-Katz method for helminth diagnosis.

Comparison of the Kato-Katz thick smear and McMaster egg counting techniques for monitoring drug efficacy against soil-transmitted helminths in schoolchildren on Pemba Island, Tanzania.

The Kato-Katz thick smear technique is widely used to assess prevalence and intensity in soil-transmitted helminth (STH) control programmes, but its usefulness in monitoring anthelminthic drug efficacy needs to be validated and compared with other methods. A promising alternative is the McMaster egg counting technique. In the present study, the efficacy of single-dose albendazole against STH infections in 430 schoolchildren on Pemba Island was assessed using both the Kato-Katz and McMaster techniques. The study revealed comparable drug efficacy results for both methods and confirmed the potency of the McMaster technique as an alternative method for monitoring large-scale deworming programmes.

Epidemiology of streptococcus group A in school aged children in Pemba.

BACKGROUND: In Pemba (Zanzibar) all the risk factors which favour Group A Streptococci spreading, infections and late sequelae are present, though GAS epidemiology is unknown. OBJECTIVE: To determine the prevalence of GAS pharyngeal carriers among school-aged-children. DESIGN: Community-based cross sectional study, carried out at the end of the dry season (January-February 2001). SETTING: Eight primary schools over the four Pemba districts were included in the study. SUBJECTS AND METHODS: Two thousand two hundred and eighty six children aged 7-10 years were selected by random sampling and submitted to throat-swab after informed consent. Swabs were processed according to the "Lennette Manual of Clinical Microbiology" 7th Ed. Isolated were tested for antibiotic susceptibility toward penicillins, erythromycin, clindamycin, josamycin, cloramphenicol, levofloxacin, rifampin and tetracyclines. RESULTS: Twenty seven point six percent of school-aged children harboured beta-haemolytic Streptococci in their pharynx; most of the isolates were serologically identified as non Group A streptococci group C and G represented more than 70% of all strains, 38.8% of whom were identified as group G; the prevalence of group A streptococci carriers among healthy children all over the island was 8.6%; group A streptococci isolates were sensitive to all the antibiotic tested, except tetracyclines, towards which 83.2% of strains were resistant. CONCLUSION: This is the first research in the field of bacteriology carried out in Pemba. According to the epidemiology of group A streptococci and to the environmental and underlying factors which predispose to late group A streptococci sequelae, we suggest to consider antibiotic treatment for children presenting with sore throat with fever and swollen cervical lymphonodes without cough or coryza.