Shahid Rasool

Enhanced disease surveillance through private health care sector cooperation in Karachi, Pakistan: experience from a vaccine trial

INTRODUCTION In research projects such as vaccine trials, accurate and complete surveillance of all outcomes of interest is critical. In less developed countries where the private sector is the major health-care provider, the private sector must be included in surveillance systems in order to capture all disease of interest. This, however, poses enormous challenges in practice. The process and outcome of recruiting private practice clinics for surveillance in a vaccine trial are described. METHODS The project started in January 2002 in two urban squatter settlements of Karachi, Pakistan. At the suggestion of private practitioners, a phlebotomy team was formed to provide support for disease surveillance. Children who had a reported history of fever for more than three days were enrolled for a diagnosis. RESULTS Between May 2003 and April 2004, 5540 children younger than 16 years with fever for three days or more were enrolled in the study. Of the children, 1312 (24%) were seen first by private practitioners; the remainder presented directly to study centres. In total, 5329 blood samples were obtained for microbiology. The annual incidence of Salmonella typhi diagnosed by blood culture was 407 (95% confidence interval (95% CI), 368-448) per 100 000/year and for Salmonella paratyphi A was 198 (95% CI, 171-227) per 100 000/year. Without the contribution of private practitioners, the rates would have been 240 per 100 000/year (95% CI, 211-271) for S. typhi and 114 (95% CI, 94-136) per 100 000/year for S. paratyphi A. CONCLUSION The private sector plays a major health-care role in Pakistan. Our experience from a surveillance and burden estimation study in Pakistan indicates that this objective is possible to achieve but requires considerable effort and confidence building. Nonetheless, it is essential to include private health care providers when attempting to accurately estimate the burden of disease in such settings.

Lessons and implications from a mass immunization campaign in squatter settlements of Karachi, Pakistan: an experience from a cluster-randomized double-blinded vaccine trial [NCT00125047].

ObjectiveTo determine the safety and logistic feasibility of a mass immunization strategy outside the local immunization program in the pediatric population of urban squatter settlements in Karachi, Pakistan.MethodsA cluster-randomized double blind preventive trial was launched in August 2003 in 60 geographic clusters covering 21,059 children ages 2 to 16 years. After consent was obtained from parents or guardians, eligible children were immunized parenterally at vaccination posts in each cluster with Vi polysaccharide or hepatitis A vaccine. Safety, logistics, and standards were monitored and documented.ResultsThe vaccine coverage of the population was 74% and was higher in those under age 10 years. No life-threatening serious adverse events were reported. Adverse events occurred in less than 1% of all vaccine recipients and the main reactions reported were fever and local pain. The proportion of adverse events in Vi polysaccharide and hepatitis A recipients will not be known until the end of the trial when the code is broken. Throughout the vaccination campaign safe injection practices were maintained and the cold chain was not interrupted. Mass vaccination in slums had good acceptance. Because populations in such areas are highly mobile, settlement conditions could affect coverage. Systemic reactions were uncommon and local reactions were mild and transient. Close community involvement was pivotal for information dissemination and immunization coverage.ConclusionThis vaccine strategy described together with other information that will soon be available in the area (cost/effectiveness, vaccine delivery costs, etc) will make typhoid fever control become a reality in the near future.

Use of satellite imagery in constructing a household GIS database for health studies in Karachi, Pakistan

BackgroundHousehold-level geographic information systems (GIS) database are usually constructed using the geographic positioning system (GPS). In some research settings, GPS receivers may fail to capture accurate readings due to structural barriers such as tall buildings. We faced this problem when constructing a household GIS database for research sites in Karachi, Pakistan because the sites are comprised of congested groups of multi-storied building and narrow lanes. In order to overcome this problem, we used high resolution satellite imagery (IKONOS) to extract relevant geographic information.ResultsThe use of IKONOS satellite imagery allowed us to construct an accurate household GIS database, which included the size and orientation of the houses. The GIS database was then merged with health data, and spatial analysis of health was possible.ConclusionsThe methodological issues introduced in this paper provide solutions to the technical barriers in constructing household GIS database in a heavily populated urban setting.

A comparison of disease caused by Shigella and Campylobacter species: 24 months community based surveillance in 4 slums of Karachi, Pakistan.

Despite the efforts of the international community diarrheal diseases still pose a major threat to children in children less than five years of age. Bacterial diarrhea has also emerged as a public health concern due to the proliferation of drug resistant species in many parts of the world. There is a paucity of population-based data about the incidence of shigellosis and Campylobacter infections in Pakistan. We report country specific results for Shigella diarrhea that were derived from a multicenter study conducted in six Asian countries. Disease surveillance was conducted over a 24 month period in urban slums of Karachi, Pakistan, a city with a population of 59,584. Cases were detected through passive detection in study treatment centers. Stool specimens or rectal swabs were collected from all consenting patients. Between January 2002 and December 2003 10,540 enteric infection cases were detected. The incidence rate of treated diarrhea in children under 5 was 488/1000/year. In children, 5 years and older, the diarrhea rate was 22/1000/year. 576 (7%) Campylobacter isolates were detected. The pre-dominant Campylobacter species was C. jenuni with an increase of 29/1000 year in children under 5 years. Shigella species were isolated from 394 of 8032 children under 5 years of age. Shigella flexneri was the dominant species (10/1000/year in children under 5 years) followed by Shigella sonnei (3.9/1000/year), Shigella boydii (2.0/1000/year) and Shigella dysenteriae (1.3/1000/year). Shigellosis and Campylobacter infection rates peaked during the second year of life. The incidence rate of shigellosis increased in old age but such a trend was not observed in Campylobacter infections. Of 394 shigellosis patients 123 (31%) presented with dysentery in contrast to only 54 (9%) of 576 patients with Campylobacter infections (p<0.001). Both Campylobacter infections and shigellosis are common in community settings of Pakistan but shigellosis presented more frequently with abdominal pain and dysentery than Campylobacter infections indicating that shigellosis may be a more severe illness than Campylobacter infections. Due to the increased and disease severity, drug resistant shigella have become a significant health problem; moreover it is a disease of poor and impoverished people who do not have the access to standard water and sanitary conditions, health care services or optimal treatment. In the face of these facts it is empirically important to develop a low cost effective vaccine that can protect these populations for a longer duration.

Relationship between vitamin B12, folate and homocysteine levels and H. Pylori infection in patients with functional dyspepsia: A cross-section study

BackgroundH. pylori infection has been associated with many micronutrient deficiencies. There is a dearth of data from communities with nutritional deficiencies and high prevalence of H. pylori infection. The aim of this study was to determine the impact of H. pylori infection on serum levels of vitamin B12, folate and homocysteine in patients with functional dyspepsia (FD).MethodsOne hundred and thirty-two patients with FD undergoing gastroscopy were enrolled. The serum was analyzed for B12, folate and homocysteine levels before gastroscopy. H. pylori infection was diagnosed by histopathological examination of gastric biopsies and urea breath test. An independent sample t-test and the Mann–Whitney test were used to compare mean serum concentrations of biomarkers between H. pylori- positive and H. pylori- negative groups of patients. A Chi-square test was performed to assess the differences among proportions, while Spearman’s rho was used for correlation analysis between levels of B12 and homocysteine.ResultsThe mean age of the group was 40.3 ± 11.5 (19–72) years. Folate deficiency was seen in 43 (34.6%), B12 deficiency in 30 (23.1%) and hyperhomocysteinemia in 60 (46.2%) patients. H. pylori was present in 80 (61.5%) patients with FD while it was absent in 50 (38.5%). Mean serum levels of B12, folate and homocysteine in the H. pylori- positive group of patients were not significantly different from the levels in the H. pylori- negative group (357 ± 170 vs. 313 ± 136 pg/mL; p = 0.13), (4.35 ± 1.89 vs. 4.42 ± 1.93 ng/mL; p = 0.84); (15.88 ± 8.97 vs. 16.62 ± 7.82 μmol/L; p = 0.24); respectively.B12 deficiency (≤200 pg/mL) was 23.8% in the H. pylori- positive patients versus 22.0% in the H. pylori- negative patients. Folate deficiency (≤3.5 ng/mL) was 33.8% in the H. pylori- positive group versus 36% in the H. pylori- negative group. Hyperhomocysteinemia (>15 μmol/L) was present in 46.2% of H. pylori- positive patients compared to 44% in the H. pylori- negative group. Correlation analysis indicated that serum B12 levels were inversely associated with serum levels of homocysteine in patients with FD (rho = −0.192; p = 0.028).ConclusionsThis study demonstrated an inverse relationship between serum levels of B12 and homocysteine in patients with FD. Moreover, no impact of the presence of H. pylori was found on B12, folate and homocysteine levels in such patients.