Typhoid fever in children in Africa

Estimates for the year 2000 suggested that there were approximately 21.5 million infections and 200,000 deaths from typhoid fever globally each year, making the disease one of the most serious infectious disease threats to public health on a global scale. However, these estimates were based on little data, especially from Africa. Global prominence and high-profile outbreaks have created the perception in Kenya that typhoid is a common cause of febrile illness. The Widal test is used widely in diagnosis. We have reviewed recent literature, taking the perspective of a healthcare provider, to collate information on the prevalence of typhoid in children particularly, and to explore the role of clinical diagnosis and diagnosis based on a crude, but common, interpretation of the Widal test. Data suggest that typhoid in children in rural Africa is uncommon, perhaps 100 times or 250 times less common than invasive disease because of Haemophilus influenzae or Streptococcus pneumoniae, respectively. Frequent use of the Widal test may result in many hundreds of over-treatment episodes for every true case treated and may perpetuate the perception that typhoid is common. Countries such as Kenya need better bacterial disease surveillance systems allied to better information for healthcare providers to promote appropriate decision-making on prevention and treatment strategies.     

Incidence of cancer esophagus in Quetta and Karachi, Pakistan.

OBJECTIVE: To study the differences in the incidence of cancer esophagus in Karachi and Quetta, Pakistan. METHODS: Incident cases of cancer esophagus registered from January 1, 1995 to December 31, 2000 were included for Karachi South, and those registered from January 1, 1998 to December 31, 2000 were included for Karachi Division and Quetta. RESULTS: In Quetta, cancer esophagus had age-standardized incidence rate (ASIR) of 25.5/100,000 population in males and 23.4/100,000 population in females, and it was the commonest malignancy in both genders. In comparison, in Karachi South and Karachi Division, cancer esophagus ranked 7th among cancers in males (ASIR 6.2/100,000 and 5.0/100,000 population, respectively) and 5th in females (7.0/100,000 and 4.9/100,000 population, respectively). The ASIR was similar among males and females in all data sets. CONCLUSION: The incidence of cancer esophagus in Quetta is comparable to that in high-incidence regions, whereas the incidence in Karachi is similar to that in moderate-incidence zones. In contrast to other world regions, cancer esophagus was equally common in males and females in Pakistan. The high risk in Quetta warrants investigation for risk factors and a targeted cancer control program.     

Patients' perceptions of blood transfusion risks in Karachi, Pakistan.

OBJECTIVE: To evaluate the understanding of and attitudes toward risks of blood transfusions among transfusion recipients in Karachi. METHODS: One hundred forty-one transfusion recipients from 13 major Karachi hospitals were interviewed. Indications for transfusion were obtained by reviewing the patients' medical records. RESULTS: The most common indications for transfusion were surgical complications (n = 77, 55%), anemia (n = 34, 24%), and generalized weakness (n = 15, 11%). Most recipients (n = 103, 80%) had never heard of viral hepatitis, and 44 (31%) had never heard of acquired immunodeficiency syndrome (AIDS). Ninety-four recipients (66%) believed that generalized weakness was a valid indication for blood transfusion. Sixty-nine recipients (49%) were not willing to pay an increased price for blood that was screened for blood-borne pathogens. CONCLUSIONS: Blood recipients in Karachi are unaware of the risks of transfusions, and the reasons given by the ordering physician for many of the transfusions were not consistent with international guidelines. Steps to educate the public about the risks of transfusions and practitioners about the indications for transfusion could prevent blood-borne virus transmission in Karachi.     

A low-cost intervention for cleaner drinking water in Karachi, Pakistan.

OBJECTIVE: To pilot test an inexpensive, home-based water decontamination and storage system in a low-income neighborhood of Karachi. METHODS: Fifty households received a 20-L plastic water storage vessel with a high-quality spout and a regular supply of diluted hypochlorite solution. Twenty-five control households were recruited. Water samples were collected at baseline and during unannounced follow-up visits 1, 3, 6, and 10 weeks later. RESULTS: Baseline drinking water samples among intervention households were contaminated with a mean 9397 colony-forming units (cfu)/100 mL of thermotolerant coliforms compared with a mean 10,990 cfu/100 mL from controls. After intervention the mean concentration of thermotolerant coliforms decreased by 99.8% among the intervention households compared with an 8% reduction among controls. Two years after vessel distribution, 34 (68%) of the families were still using the vessel. Thirteen of the households had stopped using their vessel because it had broken after more than 6 months of use, a pattern most consistent with ultraviolet radiation-induced degradation of the plastic. CONCLUSIONS: In a highly contaminated environment, a specifically designed water storage container and in-home water chlorination was acceptable and markedly improved water quality. Where plastic water vessels will be exposed to substantial sunlight, ultraviolet light stabilizers should be incorporated into the plastic.     

Epidemic non-A non-B hepatitis in urban Karachi, Pakistan

An outbreak of icteric non-A non-B (NANB) hepatitis occurred in a residential community of urban Karachi, Pakistan, from August 1986 through October 1986. Of the 114 cases reported from this community during the 1986 calendar year, a clustering of 85 cases was seen during the above period. Twenty-seven percent of 226 households and 9% of 1,250 individuals were affected. Five persons were hospitalized and 1 death occurred in a young pregnant woman. Cases occurred predominantly in the less than or equal to 29-year-old age group (72%), with a male:female ratio of 1.8:1. Thirty-four cases occurred singly within households, while in 28 households multiple cases were seen. Analysis of the epidemic curve and intervals of onset of multiple cases within households suggested prolonged common source exposure rather than secondary person-to-person transmission. No single water source was implicated but a contaminated municipal supply was presumed. Information collected from several other communities and from a university hepatitis reference laboratory suggested that the outbreak was part of a larger urban epidemic of NANB hepatitis. Based upon this investigation and data from recently published reports, it is concluded that NANB hepatitis is endemic in Pakistan.     

Hepatitis B and C: prevalence and risk factors associated with seropositivity among children in Karachi, Pakistan

Background  

Infections with hepatitis B virus (HBV) and hepatitis C virus (HCV) can lead to chronic liver disease and hepato-cellular carcinoma (HCC). This cross-sectional study estimated the prevalence and identified risk factors associated with Hepatitis B surface antigen (HBsAg) and HCV antibody (anti-HCV) sero-positivity among children 1 to 15 years of age.     

Limited effectiveness of home drinking water purification efforts in Karachi, Pakistan.

OBJECTIVE: In many developing-country urban areas, municipally supplied water is not microbiologically safe. This study evaluated drinking water quality and effect of home water purification efforts in Karachi, Pakistan. METHODS: Members of 300 households, including 100 households who used the Aga Khan University Hospital Laboratory and 200 of their neighbors were interviewed. In 293 consenting households, structured observations were performed and drinking water was analyzed for the presence of coliforms, using the multiple tube fermentation technique. RESULTS: Although 193 of the 293 households (66%) reported using some method to purify their drinking water, including 169 (58%) who boiled their water, only 48 (16%) of the drinking water samples were free of coliforms. Although a combination of boiling and filtering was the most effective method of purification, only 38% of samples that had been boiled and filtered were free of coliforms. CONCLUSIONS: Further refinements and evaluations of home-based efforts to purify and store water are needed.     

Hemoglobinopathies among five major ethnic groups in Karachi,Pakistan

A brief survey of abnormal hemoglobin variants among the major ethnic groups of Karachi was conducted; 202,600 subjects were studied. Patients with low hemoglobin (Hb), low mean cell volume (MCV) and mean cell hemoglobin (MCH) including anemia, microcytosis, hypochromic hemolysis and target cells, were refered for the identification of hemoglobinopathy by molecular methods. Population screening showed that 60% had iron-deficiency anemia and 40% had hemolytic anemia, of which 20.6% was due to beta-thalassemia major, 13% beta-thalassemia trait, 5.1% sickle cell disease, 0.76% hemoglobin D Punjab (HbD Punjab), 0.32% hemoglobin C (HbC), and 0.22% hereditary persistence of fetal hemoglobin (HPFH).     

Prevalence of non-Helicobacter pylori duodenal ulcer in Karachi, Pakistan

AIM:To determine the prevalence of non-Helicobacter pylori (H pylori)-related duodenal ulcer in patients with acid-peptic diseases. METHODS: Medical records of patients who attended the Gastroenterology Department at Aga Khan University Hospital from 1999 to 2001 and had endoscopic diagnosis of duodenal ulcers were reviewed. Duodenal ulcer associated with H pylori was diagnosed on the basis of endoscopy, rapid urease test and histopathology whereas histories of aspirin or other non-steroidal anti-inflammatory drugs (NSAIDs) related duodenal ulcers. Non-H pylori, non-NSAID duodenal ulcers were those without H pylori infection and history of NSAID intake. Co-morbid conditions associated were noted. RESULTS: Of 2 260 patients, 10% (217/2 260) had duodenal ulcer. Duodenal ulcer related to H pylori infection accounted for 53% (116/217), NSAID-related 10% (22/217), non-H pylori non-NSAID 29% (62/217), and 8% (17/217) had both H pylori infection and histories of NSAID intake. Fifteen percent (18/116)_patients had past histories of peptic ulcer disease in H pylori infection, while 8% (5/62) in non-H pylori non-NSAID ulcer. Co-morbid conditions in H pylori infection were seen in 23% (27/116) and 34% (21/62) in non-H pylori non-NSAID ulcer. CONCLUSION: Incidence of H pylori infection related with duodenai ulcer is common. In the presence of co-morbids, non-H pylori and non-NSAID duodenal ulcer is likely to be present.     

Typhoid fever: pathogenesis and disease

Typhoid fever is an infectious disease of global distribution. Although there is a wealth of data on Salmonella typhimurium infection in the mouse and the interaction of this serovar with human cell lines in vitro, there is a relatively small amount of data on S. typhi and the pathogenesis of typhoid fever. In this review we focus on three areas: adherence to and invasion of gut epithelial cells, dissemination to systemic sites, and survival and replication within host cells. In addition, we attempt to put current salmonella research into the context of typhoid fever.     

Background demographics and risk behaviors of injecting drug users in Karachi, Pakistan.

OBJECTIVE: To find the prevalence of HIV infection and risk behaviors among injecting drug users (IDUs) in Karachi, Pakistan. DESIGN: A cross-sectional study of IDUs conducted in Karachi, Pakistan from February through June 1996. RESULTS: Of the 242 IDUs, 11 (4%) refused HIV testing. One (0.4%; 95% confidence interval (CI) = 0.37-0.48%) was HIV positive. All subjects were male. Over the past 6 months 47% had engaged in receptive needle sharing, 38% had perceived a change in their social network, 22% had had sexual intercourse, of whom only 7% always used condoms, and none had washed their needles with bleach. Younger age (28 vs. 31 years; p = 0.01), younger age at first injection (25 vs. 28 years; p = 0.001), fewer years of schooling (3 vs. 5 years; p = 0.001), lower monthly income (70 dollars vs. 80 dollars; p = 0.03), inhaling fumes of heroin from a foil in the year before injecting (OR = 4.8; CI = 2.2-10.3), injecting first time with heroin (OR = 3.6; CI = 1.2-12.6), having a temporary job (OR = 2.5; CI = 1.2-5.2), and a perceived change in one's social network (OR = 4.4; CI = 2.4-7.9) were all associated with receptive needle sharing. IDUs who knew about HIV spread through contaminated needles were less likely to share (OR = 0.4; CI 0.2-0.8). In the final logistic regression model receptive needle sharing was associated with inhaling of fumes of heroin on a foil in the year prior to injecting (adjusted OR = 5.6; CI = 2.6-12.0), a perceived change in one's social network (adjusted OR = 4.0; CI = 2.2-7.4), and inversely associated with age at first time of injection (beta = -0.07; p = 0.002). CONCLUSION: Background HIV prevalence was low among IDUs in Karachi despite high-risk behavior in 1996. In order to control HIV transmission among IDUs in Pakistan, continual HIV surveillance with well-coordinated and effective HIV risk reduction, and drug demand reduction programs need to be implemented among drug users.