Cholera in the United States, 2001-2011: a reflection of patterns of global epidemiology and travel.

US cholera surveillance offers insight into global and domestic trends. Between 2001 and 2011, 111 cases were reported to the Centers for Disease Control and Prevention. Cholera was associated with international travel in 90 (81%) patients and was domestically acquired in 20 (18%) patients; for one patient, information was not available. From January 2001 to October 2010, the 42 (47%) travel-associated cases were associated with travel to Asia. In October 2010, a cholera epidemic started in Haiti, soon spreading to the Dominican Republic (Hispaniola). From then to December 2011, 40 (83%) of the 48 travel-associated cases were associated with travel to Hispaniola. Of 20 patients who acquired cholera domestically, 17 (85%) reported seafood consumption; 10 (59%) ate seafood from the US Gulf Coast. In summary, an increase in travel-associated US cholera cases was associated with epidemic cholera in Hispaniola in 2010-2011. Travel to Asia and consumption of Gulf Coast seafood remained important sources of US cholera cases.

Real-time modelling used for outbreak management during a cholera epidemic, Haiti, 2010-2011.

The emergence of epidemic cholera in post-earthquake Haiti portended a public health disaster of uncertain magnitude. In order to coordinate relief efforts in an environment with limited healthcare infrastructure and stretched resources, timely and realistic projections of the extent of the cholera outbreak were crucial. Projections were shared with Government and partner organizations beginning 5 days after the first reported case and were updated using progressively more advanced methods as more surveillance data became available. The first projection estimated that 105 000 cholera cases would occur in the first year. Subsequent projections using different methods estimated up to 652 000 cases and 163 000-247 000 hospitalizations during the first year. Current surveillance data show these projections to have provided reasonable approximations of the observed epidemic. Providing the real-time projections allowed Haitian ministries and external aid organizations to better plan and implement response measures during the evolving epidemic.

Epidemiological features of a newly described serotype of Shigella boydii.

We report the clinical, microbiological, and epidemiological features of an emerging serotype, Shigella boydii 20. We interviewed patients about symptoms, and history of travel and visitors during the week before illness onset. Seventy-five per cent of the 56 patients were Hispanic. During the week before illness onset, 18 (32%) travelled abroad; 17 (94%) had visited Mexico. Eight (21%) out of 38 who had not travelled had foreign visitors. There were eight closely related patterns by PFGE with XbaI. S. boydii 20 may be related to travel to Mexico and Hispanic ethnicity. Prompt epidemiological investigation of clusters of S. boydii 20 infection may help identify specific vehicles and risk factors for infection.

Cholera in the United States, 1995-2000: trends at the end of the twentieth century.

To evaluate recent trends in cholera in the United States, surveillance data from all cases of laboratory-confirmed toxigenic Vibrio cholerae O1 and O139 infection reported to the Centers for Disease Control and Prevention between 1995 and 2000 were reviewed. Sixty-one cases of cholera, all caused by V. cholerae O1, were reported. There was 1 death, and 35 (57%) of the patients were hospitalized. Thirty-seven (61%) infections were acquired outside the United States; 14 (23%) were acquired through undercooked seafood consumed in the United States, 2 (3%) were acquired through sliced cantaloupe contaminated by an asymptomatically infected food handler, and no source was identified for 8 (13%) infections. The proportion of travel-associated infections resistant to trimethoprim-sulfamethoxazole, sulfisoxazole, streptomycin, and furazolidone increased from 7 (8%) of 88 in 1990-1994 to 11 (31%) of 35 in 1995-2000. Foreign travel and undercooked seafood continue to account for most US cholera cases. Antimicrobial resistance has increased among V. cholerae O1 strains isolated from ill travelers.

Helicobacter pylori and epidemic Vibrio cholerae O1 infection in Peru.

In a cross-sectional study of the 1991 Peruvian cholera epidemic, Vibrio cholerae O1 infection was associated with Helicobacter pylori infection, particularly in young children. These data support the hypothesis that hypochlorhydria induced by H. pylori is important in the pathogenesis of diarrhoeal disease.

Diarrhoea prevention in Bolivia through point-of-use water treatment and safe storage: a promising new strategy.

A novel water quality intervention that consists of point-of-use water disinfection, safe storage and community education was field tested in Bolivia. A total of 127 households in two periurban communities were randomized into intervention and control groups, surveyed and the intervention was distributed. Monthly water quality testing and weekly diarrhoea surveillance were conducted. Over a 5-month period, intervention households had 44% fewer diarrhoea episodes than control households (P = 0.002). Infants < 1 year old (P = 0.05) and children 5-14 years old (P = 0.01) in intervention households had significantly less diarrhoea than control children. Campylobacter was less commonly isolated from intervention than control patients (P = 0.02). Stored water in intervention households was less contaminated with Escherichia coli than stored water in control households (P < 0.0001). Intervention households exhibited less E. coli contamination of stored water and less diarrhoea than control households. This promising new strategy may have broad applicability for waterborne disease prevention.

An outbreak of Brainerd diarrhea among travelers to the Galapagos Islands.

In 1992, an outbreak of chronic diarrhea occurred among passengers on a cruise ship visiting the Galapagos Islands, Ecuador. Passengers (548) were surveyed, and stool and biopsy specimens from a sample who reported chronic diarrhea were examined. On completed questionnaires, returned by 394 passengers (72%), 58 (15%) reported having chronic diarrhea associated with urgency (84%), weight loss (77%), fatigue (71%), and fecal incontinence (62%). Illness began 11 days (median) after boarding the ship and lasted 7 to >42 months. Macroscopic and histologic abnormalities of the colon were common, but extensive laboratory examination revealed no etiologic agent. No one responded to antimicrobial therapy. Patients were more likely than well passengers to have drunk the ship's unbottled water or ice before onset of illness and to have eaten raw sliced fruits and vegetables washed in unbottled water. Water handling and chlorination on the ship were deficient. Outbreaks of a similar illness, Brainerd diarrhea, have been reported in the United States. Although its etiology remains unknown, Brainerd diarrhea may also occur among travelers.

Etiology of bloody diarrhea in Bolivian children: implications for empiric therapy. Bolivian Dysentery Study Group.

In Bolivia, few data are available to guide empiric therapy for bloody diarrhea. A study was conducted between December 1994 and April 1995 to identify organisms causing bloody diarrhea in Bolivian children. Rectal swabs from children <5 years old with bloody diarrhea were examined for Salmonella, Shigella, and Campylobacter organisms; fecal specimens were examined for Entamoeba histolytica. A bacterial pathogen was identified in specimens from 55 patients (41%). Shigella organisms were found in 39 specimens (29%); 37 isolates (95%) were resistant to ampicillin, 35 (90%) to trimethoprim-sulfamethoxazole, and 24 (62%) to chloramphenicol, but all were susceptible to nalidixic acid. Only 1 of 133 stool specimens contained E. histolytica trophozoites. Multidrug-resistant Shigella species are a frequent cause of bloody diarrhea in Bolivian children; E. histolytica is uncommon. Clinical predictors described in this study may help identify patients most likely to have Shigella infection. Laboratory surveillance is essential to monitor antimicrobial resistance and guide empiric treatment.

Narrow-mouthed water storage vessels and in situ chlorination in a Bolivian community: a simple method to improve drinking water quality.

Epidemiologic investigations of the Latin America cholera epidemic have repeatedly implicated untreated drinking water and water touched by hands during storage as important vehicles for disease transmission. To prevent such transmission, we provided a new narrow-mouthed, plastic, water storage vessel and 5% calcium hypochlorite solution for home disinfection of stored water to a Bolivian Aymara Indian community at risk for cholera. We evaluated acceptance of this intervention and its effect on water quality. Each of 42 families in the study obtained water from a household well; fecal coliform bacteria were found in water from 39 (93%) of 42 wells and 33 (79%) of 42 usual water storage vessels. One group of families received the special vessels and chlorine (group A), a second received only the special vessels (group B), and a third served as a control group (group C). Water samples collected every three weeks from group A special vessels had lower geometric mean fecal coliform colony counts (P < 0.0001) and lower geometric mean Escherichia coli colony counts (P < 0.0001) than water from group B or C vessels. Adequate levels of free chlorine persisted in these vessels for at least 5 hr. The special vessels and chlorine solution were well accepted and continued to be used for at least six months. Use of the vessel and chlorine solution produced drinking water from nonpotable sources that met World Health Organization standards for microbiologic quality.

Severe life-threatening cholera associated with blood group O in Peru: implications for the Latin American epidemic.

A household survey in 1991, at the onset of the Latin American cholera epidemic, investigated high attack rates in Trujillo, Peru, and determined the association between blood group O and severe cholera. Of 463 persons in 69 households, 173 (37%) reported diarrhea, 21% required rehydration therapy, and 4% were hospitalized; these treatment requirements greatly exceeded estimates based on other populations. Elevated vibriocidal or antitoxic antibody titers were present in 52% of 321 from whom serum was obtained; 73% were blood group O. Blood group O was strongly associated with severe cholera: Infected persons had more diarrheal stools per day than persons of other blood groups, were more likely to report vomiting and muscle cramps, and were almost eight times more likely to require hospital treatment. Since prevalence of blood group O in Latin America may be the world's highest, estimates of treatment requirements should be increased to prevent unnecessary deaths.

Epidemic cholera in Ecuador: multidrug-resistance and transmission by water and seafood.

To determine risk factors for cholera in an epidemic-disease area in South America, a case-control investigation was performed in Guayaquil, Ecuador, in July 1991. Residents > 5 years old who were hospitalized for treatment of acute, watery diarrhoea and two matched controls for each were interviewed regarding sources of water and food, and eating, drinking, and hygienic habits. Interviewers inspected homes of case-patients and controls to document water treatment, food-handling, and hygienic practices. Faecal specimens and shellfish were cultured for Vibrio cholerae O 1. Isolates were tested for susceptibility to a variety of antimicrobial agents. Drinking unboiled water (odds ratio [OR] = 4.0, confidence interval [CI] = 1.8-7.5), drinking a beverage from a street vendor (OR = 2.8, CI = 1.3-5.9), eating raw seafood (OR = 3.4, CI = 1.4-11.5), and eating cooked crab (OR = 5.1, CI = 1.4-19.2) were associated with illness. Always boiling drinking water at home (OR = 0.5, CI = 0.2-0.9) was protective against illness. The presence of soap in either the kitchen (OR = 0.3, CI = 0.2-0.8) or bathroom (OR = 0.4, CI = 0.2-0.9) at home was also protective. V. cholerae O 1 was recovered from a pooled sample of a bivalve mollusc and from 68% of stool samples from case-patients. Thirty-six percent of the isolates from stool specimens were resistant to multiple antimicrobial agents. Specific prevention measures may prevent transmission through these vehicles in the future. The appearance of antimicrobial resistance suggests the need for changes in current methods of prevention and treatment.

Waterborne transmission of epidemic cholera in Trujillo, Peru: lessons for a continent at risk.

The epidemic of cholera that began in Peru in January, 1991, marked the first such epidemic in South America this century. Subsequently, over 533,000 cases and 4700 deaths have been reported from nineteen countries in that hemisphere. We investigated the epidemic in Trujillo, the second largest city in Peru. Trujillo's water supply was unchlorinated and water contamination was common. Suspect cholera cases were defined as persons presenting to a health facility with acute diarrhoea between Feb 1, and March 31, 1991. We studied a cohort of 150 patients who had been admitted to hospital and conducted a matched case-control study with 46 cases and 65 symptom-free and serologically uninfected controls; we also carried out a water quality study. By March 31, 1991, 16,400 cases of suspected cholera (attack rate 2.6%), 6673 hospital admissions, and 71 deaths (case-fatality rate 0.4%) had been reported in the province of Trujillo. 79% of stool cultures of patients with diarrhoea presenting to a single hospital yielded Vibrio cholerae O1. In the case-control study, drinking unboiled water (odds ratio [OR] 3.1, 95% confidence interval [CI] 1.3-7.3), drinking water from a household water storage container in which hands had been introduced into the water (4.2, 1.2-14.9), and going to a fiesta (social event) (3.6, 1.1-11.1) were associated with illness. The water quality study showed progressive contamination during distribution and storage in the home: faecal coliform counts were highest in water from household storage containers and lowest in city well water. V cholerae O1, biotype El Tor, serotype Inaba, was isolated from three city water samples. Cholera control measures in Trujillo should focus on treatment of water and prevention of contamination during distribution and in the home. Trujillo's water and sanitation problems are common in South America; similar control measures are needed throughout the continent to prevent spread of epidemic cholera.

PIP: Researchers conducted various studies simultaneously in Trujillo. Peru (population 626,456) in March 1991 to set up a cholera surveillance system and to determine clinical characteristics of suspect cholera cases, modes of transmission, and municipal water quality during distribution and storage. These studies occurred after the population received information on how to avoid cholera. The cholera attack rate for the 1st 2 months of the epidemic stood at 2.6% (16,400 cases). The case fatality rate was 0.4% (71 deaths). The median hours between onset of symptoms and arrival at Belen hospital were 12 hours. 56% of the patients were treated with oral rehydration solution before coming to the hospital and 13% with homemade rehydration solution. Laboratory personnel isolated toxigenic nonhemolytic Vibrio cholera 01, biotype El Tor, serotype Inaba from the rectal swabs of 79% of cholera patients. None of the hospital patients died. 29% of controls from the case control study claimed to not have witnessed a personal or household attack of diarrhea recently, yet their vibrocidal antibody titers indicated a recent cholera infection. 58% of cases drank unboiled water within 3 days of falling ill compared to only 28% of controls (matched odds ratio [OR] 3.1; p.05). Other significant risk factors (p.05) were drank water from container also used to dip hands (OR 4.2) and attended a fiesta (OR 3.6). There were significantly more total coliforms in water containers than tap water and municipal water (mean 794 vs. 6 and 1 respectively; p.05). The same was true for fecal coliforms (20 vs. 2 and 1 respectively). In conclusion, the drinking water was contaminated with V. cholera. Eventually the city should eliminate cross connections, provide continuous supplies of water at high pressure, and improve the sewage system.