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Cholera is endemic in Bangladesh, and a regular seasonal pattern of cholera epidemics occurs. We examined the clonal relationships among 103 clinical and environmental Vibrio cholerae isolates belonging to O1, O139, or non-O1 non-O139 serogroups isolated during epidemic and interepidemic periods in Bangladesh and compared them with those of 51 V. cholerae isolates from four countries in Asia and Africa. These studies were done by a computer-assisted numerical analysis of the restriction endonuclease cleavage patterns of rRNA genes (ribotypes). Unweighed pair-group cluster analysis of BglI- and HindIII-generated band patterns revealed 16 clusters. Ribotypes were defined as clusters of strains possessing > 98% similarity. The results showed that 154 isolates could be differentiated into 15 different ribotypes, and strains belonging to 3 of these ribotypes (ribotypes I, V, and VIIIA and VIIIB) were isolated more frequently during the epidemic periods than during interepidemic periods in Bangladesh. Classical vibrios belonged to six different ribotypes (ribotypes I to VI), with a mean similarity coefficient of 0.84, and the El Tor vibrios belonged to five different ribotypes (ribotypes VIIIA and IX to XII), with a mean similarity coefficient of 0.82. A single clone of El Tor vibrios (ribotype XII) was resident in Tanzania, whereas Nigeria, Syria, and India shared toxigenic El Tor strains with Bangladesh. Cholera toxin (CT)-positive O139 vibrios isolated from Bangladesh and India belonged to a single ribotype (ribotype VIIIB) and were > 98% similar to one of the ribotypes of El Tor vibrios (ribotype VIIIA), but a CT-negative O139 vibrio from Argentina (ribotype XIII) was < 75% similar to the same cluster of El Tor vibrios, thus suggesting more than one possible origin for O139 vibrios. Strains belonging to the same ribotypes (ribotypes VIII to X) were isolated from both patients and surface water in Bangladesh, indicating possible transmission through surface water. A clone of a CT-positive environmental isolate of non-O1 V. cholerae (ribotype VII) was found to be closely related (76.3% similarity) to a clone of classical vibrios (ribotype I) and was only between 27.2 and 56.1% similar to clusters of El Tor, O139, and two other non-O1 nontoxigenic clones.

In July, 1994, in one of the worst cholera outbreaks in recent times, an estimated 12,000 Rwandan refugees died in Goma in eastern Zaire. The Vibrio cholerae strains were resistant to tetracycline and doxycycline, the commonly used drugs for cholera treatment. Despite the efforts of international organisations, which provided medical relief by establishing treatment centres in Goma, mortality from the disease was much higher than expected. In the area of Muganga camp, which had the largest concentration of refugees and where most of the medical aid organisations were active, the highest reported case-fatality ratio for a single day was 48%. The slow rate of rehydration, inadequate use of oral rehydration therapy, use of inappropriate intravenous fluids, and inadequate experience of health workers in management of severe cholera are thought to be some of the factors associated with the failure to prevent so many deaths during the epidemic. In one of the temporary treatment centres with the worst case-fatality record, our team showed that improvement of these factors could increase the odds of survival of cholera patients even in a disaster setting.

For decades, epidemic cholera in Bangladesh has produced contrasting pictures of appearance and disappearance of Vibrio cholerae, which until recently, remained confined to the biotypes and to serotypes of V. cholerae O1. The classical biotype continued to survive and coexisted with El Tor biotype in southern Bangladesh despite its disappearance from the rest of the world during the present pandemic. For the first time in history, during the cholera epidemic in 1993, both biotypes (classical and El Tor) of V. cholerae O1 have disappeared and have been replaced by a new strain of V. cholerae non-O1 (designated as O139 Bengal). Environmental changes occurring in the Bay of Bengal may have resulted in the emergence of the new epidemic strain of V. cholerae in Bangladesh.

In Bangladesh, the replacement of classical Vibrio cholerae by the E1 Tor biotype in 1968 and the reappearance of the classical biotype and its coexistence with the E1 Tor biotype after 1982 were never adequately explained. We have analyzed 23 classical V. cholerae isolates collected between 1961 and 1968, 14 classical isolates collected between 1982 and 1992 from the capital city, Dhaka, and 6 classical V. cholerae isolates collected from two southern districts of Bangladesh and studied restriction endonuclease cleavage patterns of rRNA genes (ribotypes) to investigate the clonal relationships among the isolates. Southern blots of total DNA digested with restriction enzyme BamHI, BglI, EcoRI, HindIII, or PstI were probed, using a cloned Escherichia coli rRNA operon. While restriction enzymes BamHI, EcoRI, and PstI failed to differentiate the isolates on the basis of ribotyping, BglI and HindIII produced digestion patterns that allowed differentiation. Ribotyping the isolates with BglI and HindIII revealed five different clones (ribotypes IA, IB, IIA, IC, and IIC) of classical vibrios in Bangladesh. Strains belonging to ribotypes IA and IB were isolated in Dhaka before 1968, and one ribotype (IA) was again isolated between 1982 and 1992. Ribotype IIA was isolated in 1988 and 1989, when both clones (IA and IIA) of classical vibrios coexisted with the EI Tor vibrios. Isolates belonging to ribotypes IC and IIC were collected in the southern districts of Bangladesh and were clearly different from those collected in Dhaka between 1968 and 1992 by ribotyping analysis with BglI. These results support the previous assumption that classical vibrios were never completely replaced in Bangladesh and also demonstrate the existence of more than one genetically different clone of classical V. cholerae.

A double-blind, randomised, placebo-controlled trial was conducted to evaluate the safety and toxicity of vitamin A supplementation within the Expanded Programme on Immunisation (EPI) in rural Bangladesh. 191 infants received 3 doses of either 50,000 IU of vitamin A or placebo at about 1.5, 2.5, and 3.5 months and were examined on days 1, 2, 3, and 8 after supplementation. 11 infants (11.5%) supplemented with vitamin A had episodes of bulging of the fontanelle as opposed to 1 (1%) in the placebo group. 16 of the 17 events occurred in the vitamin A supplemented group. No other side effects were noted. There was a tendency towards a cumulative effect of toxicity with increasing doses.

A community-based longitudinal study was conducted in Matlab, a rural area of Bangladesh, from May 1988 to April 1989 to examine the associations among malnutrition, cell-mediated immune deficiency, and the incidence of diarrhea in children under age 5 years. A cohort of 705 children was followed for a year; illnesses were ascertained every fourth day by home visits, anthropometric status was evaluated monthly, and cell-mediated immune status was assessed by a multiple antigen skin test at baseline and every 3 months. The diarrhea incidence rate was 4.6 episodes per year. Approximately three quarters of the children were below -2 z score weight for age and height for age, and about a third were below -2 z score weight for height. There was a modest association between undernutrition and the incidence of diarrhea. About 10-20% of the study children were anergic, and these children experienced a 50% increased incidence of diarrhea compared with their immunocompetent counterparts. This association persisted after controlling for the effects of age, nutritional status, socioeconomic status, and history of diarrhea in the previous 3 months. Malnutrition and cell-mediated immune deficiency were important independent risk factors for the occurrence of diarrhea and must both be considered in the design of interventions for the control of this condition.

A longitudinal study of diarrhea was carried out from May 1988 to April 1989 by household surveillance of 705 children less than 5 years old in rural Bangladesh. Stool samples were examined for enteric pathogens at the beginning of each diarrheal episode. For persistent episodes, stool examination was repeated on days 15-17 of the illness. For each case of persistent diarrhea, stool samples from age-matched acute diarrheal and healthy controls were examined. Compared with healthy controls, cases of diarrhea were associated with Shigella species (P = .07) and rotavirus (P less than .05). Diffusely adherent Escherichia coli (P less than .05) and cryptosporidia (P = .07) were the only enteropathogens associated with persistent diarrhea in comparison with acute diarrhea. No more than 15% of children had the same class of pathogen identified from stool on both days 1-3 and days 15-17, indicating that persistent infection was uncommon. However, a different enteropathogen was frequently found on days 15-17, suggesting that sequential infection may be a cause of persistent diarrhea.

The worst flood in the history of Bangladesh affected millions of people in 1988. To determine morbidity and mortality during the flood, we investigated the causes of illness in 46,740 patients and causes of death in 154 persons while providing medical relief services in 72 flood affected upazilas (sub-districts). Diarrhoea was the most common illness (34.7%), followed by respiratory tract infections (17.4%). Watery diarrhoea was the most common type (47%) of diarrhoea and the most common cause of death for all age groups except those above 45-years of age. Respiratory disease was responsible for 13% of all reported deaths; only 7% of these were associated with acute respiratory tract infections. Accidental deaths accounted for 9.7% of the reported deaths: 5.8% of those were due to drowning, a figure twice as high as that reported previously. Our study suggests that floods have influenced the distribution of disease and death among the affected population.

During the present cholera pandemic the El Tor biotype of Vibrio cholerae has completely displaced the classic biotype, except in Bangladesh. We studied the distribution of these two biotypes in twenty-four rural districts during epidemics in 1988-89; there was clustering of the classic biotype in the southern region and of the El Tor biotype in all other regions. These findings suggest that the southern coastal region is now (and may always have been) the habitat of classic cholera. The selective distribution of V cholerae O1 biotypes in Bangladesh may have been affected by ecological changes occurring in the country.

Thirty-nine gravidae with congestive cardiac failure and ten pregnant patients with acute pulmonary edema treated at the Ahmadu Bello University Teaching Hospital in Kaduna, Nigeria, over a five-year period are presented. Congestive cardiac failure occurred more frequently in the postnatal period, and parity and socioeconomic class were not significantly related to cardiac failure. Maternal mortality was low in spite of all patients being in functional grades III and IV. Idiopathic cardiomegaly and chronic rheumatic heart disease were the most common underlying causes of heart failure in pregnancy. The dominant valvular lesions in the patients with rheumatic heart disease was mitral incompetence.

In May 1985, a cyclone from the Bay of Bengal struck the coastal islands of Bangladesh. In spite of early detection of atmospheric turbulence and the history of severe cyclones in the area, an estimated 11,000 people lost their lives. In a natural experiment, cyclone death rates from the two severely affected islands, Urir Char and Sandwip, were analysed to determine the risk factors of cyclone-associated mortality. In Urir Char, in which no cyclone shelters existed, the study group lost 40% of the family members in contrast to 3.4% from Sandwip, where at least eight cyclone shelters existed. Individuals who did not seek shelter were at the highest risk. Barriers in seeking safety were physical as well as behavioural. Easy access to shelters was a significant factor in reducing the risk. Deaths could have been averted through improved timing and method of advance warning.

In May 1985, a cyclone and tidal surge devastated Sandwip, an island off the Southern Corner of Bangladesh. Within one week after this disaster a cholera epidemic broke out. It resulted in 12,194 registered cases and 51 deaths. The factors contributing to the occurrence of the epidemic are analyzed.