WHO Cholera Fact Sheet – June 2010

June 4, 2010 Leave a comment
Fact sheet N°107 – Revised June 2010

Cholera

Key facts

  • Cholera is an acute diarrhoeal disease that can kill within hours if left untreated.
  • There are an estimated 3–5 million cholera cases and 100 000–120 000 deaths due to cholera every year.
  • Up to 80% of cases can be successfully treated with oral rehydration salts.
  • Effective control measures rely on prevention, preparedness and response.
  • Provision of safe water and sanitation is critical in reducing the impact of cholera and other waterborne diseases.
  • Oral cholera vaccines are considered an additional means to control cholera, but should not replace conventional control measures.

Link to full-text: http://www.who.int/mediacentre/factsheets/fs107/en/

Categories: Global Tags:

World and Africa Cholera Statistics, 2000-2008

May 21, 2010 Leave a comment

At the Google Fusion Table link below are statistics on cholera cases, cholera deaths and CFRs worldwide, for Africa and for specific African countries:

You can click on the VISUALIZE tab to generate graphs and charts and leave can also leave comments, questions, etc.

Please email any questions or suggestions to dcampbell@usaid.gov.

Categories: Global Tags:

Western and Central Africa – Cholera Cases 2009

November 11, 2009 Leave a comment

OCHA. July 2009. Western & Central Africa – Cholera Cases 2009. (pdf, 633KB)

Categories: 1

DR Congo – Cholera map, Oct. 2009

November 11, 2009 Leave a comment

IFRC. Oct. 6, 2009. drc-cholera_oct2009. (pdf, 913KB)

Categories: Dem. Rep. Congo Tags:

Cameroon – Cholera map, October 2009

November 11, 2009 Leave a comment

IFRC, October 26, 2009. cameroon-cholera_oct2009. (pdf, 913KB)

Categories: Cameroon

Cholera articles from the American Journal of Tropical Medicine & Hygiene

September 9, 2009 Leave a comment
 Below are links to the full-text of 16 cholera studies published from 1998-2008 in the American Journal of Tropical Medicine & Hygiene.
 
 Spatial Analysis of Risk Factor of Cholera Outbreak for 2003-2004 in a Peri-urban Area of Lusaka, Zambia. 
Satoshi Sasaki, Hiroshi Suzuki, Kumiko Igarashi, Bushimbwa Tambatamba, AND Philip Mulenga
Am J Trop Med Hyg 2008; 79: 414-421.  PDF: http://www.ajtmh.org/cgi/reprint/79/3/414>

Environmental Vibrio Cholerae O139 May Be the Progenitor of Outbreak of Cholera in Coastal Area of Orissa, Eastern India, 2000: Molecular Evidence
Hemant Kumar Khuntia, Bibhuti Bhusan Pal, Prem Kumar Meher, AND Guru Prasad Chhotray
Am J Trop Med Hyg 2008; 78: 819-822. [PDF]: http://www.ajtmh.org/cgi/reprint/78/5/819>

Local Environmental Predictors of Cholera in Bangladesh and Vietnam
Michael Emch, Caryl Feldacker, Mohammad Yunus,  et. al.
Am J Trop Med Hyg 2008; 78: 823-832. [PDF] http://www.ajtmh.org/cgi/reprint/78/5/823>

Rapid Spread of Vibrio cholerae O1 Throughout Kenya, 2005.
Isaac Mugoya, Samuel Kariuki, Tura Galgalo, et al.
Am J Trop Med Hyg 2008; 78: 527-533. [PDF]: http://www.ajtmh.org/cgi/reprint/78/3/527>
 
Cholera: A New Homeland in Africa?
Nicholas H. Gaffga, Robert V. Tauxe, AND Eric D. Mintz
Am J Trop Med Hyg 2007; 77: 705-713. [PDF]: http://www.ajtmh.org/cgi/reprint/77/4/705>

GEOGRAPHICAL DISTRIBUTION AND RISK FACTORS ASSOCIATED WITH ENTERIC DISEASES IN VIETNAM
LOUISE A. KELLY-HOPE, WLADIMIR J. ALONSO, et al. 
Am J Trop Med Hyg 2007; 76: 706-712. [PDF]: http://www.ajtmh.org/cgi/reprint/76/4/706>

REVIEW OF REPORTED CHOLERA OUTBREAKS WORLDWIDE, 1995
DAVID C. GRIFFITH, LOUISE A. KELLY-HOPE, AND MARK A. MILLER
Am J Trop Med Hyg 2006; 75: 973-977. [PDF]: http://www.ajtmh.org/cgi/reprint/75/5/973>

A CHOLERA EPIDEMIC AMONG THE NICOBARESE TRIBE OF NANCOWRY, ANDAMAN, AND NICOBAR, INDIA
ATTAYOOR P. SUGUNAN, ASIT R. GHOSH, SUBARNA ROY, MOHAN D. GUPTE, AND SUBHASH C. SEHGAL
Am J Trop Med Hyg 2004; 71: 822-827. [PDF]: http://www.ajtmh.org/cgi/reprint/71/6/822>

Cholera in Indonesia in 1993-1999.
CH Simanjuntak, W Larasati, S Arjoso, M Putri, et al.
Am J Trop Med Hyg 2001; 65: 788-797. [PDF]:  http://www.ajtmh.org/cgi/reprint/65/6/788>

Mortality, morbidity, and microbiology of endemic cholera among hospitalized patients in Dhaka, Bangladesh
ET Ryan, U Dhar, WA Khan, MA Salam,  et. al. 
Am J Trop Med Hyg 2000; 63: 12-20. [PDF]: http://www.ajtmh.org/cgi/reprint/63/1/12>

New insights on the emergence of cholera in Latin America during 1991: the Peruvian experience
N. Seas, J Miranda, AI Gil, R Leon-Barua, J Patz, A Huq, RR Colwell, AND RB Sack
Am J Trop Med Hyg 2000; 62: 513-517. [PDF]: http://www.ajtmh.org/cgi/reprint/62/4/513>

Safety, immunogenicity, and lot stability of the whole cell/recombinant B subunit (WC/rCTB) cholera vaccine in Peruvian adults and children
DN Taylor, V Cardenas, J Perez, R Puga, AND AM Svennerholm
Am J Trop Med Hyg 1999; 61: 869-873. [PDF]: http://www.ajtmh.org/cgi/reprint/61/6/869>

First do no harm: making oral rehydration solution safer in a cholera epidemic
NA Daniels, SL Simons, A Rodrigues, et. al. 
Am J Trop Med Hyg 1999; 60: 1051-1055. [PDF]: http://www.ajtmh.org/cgi/reprint/60/6/1051>

The effect of iron on the toxigenicity of Vibrio cholerae
M Patel AND M Isaacson
Am J Trop Med Hyg 1999; 60: 392-396. [PDF]: http://www.ajtmh.org/cgi/reprint/60/3/392>

Transmission of epidemic Vibrio cholerae O1 in rural western Kenya associated with drinking water from Lake Victoria: an environmental reservoir for cholera?
RL Shapiro, MR Otieno, PM Adcock, PA Phillips-Howard, et al. 
Am J Trop Med Hyg 1999; 60: 271-276. [PDF]: http://www.ajtmh.org/cgi/reprint/60/2/271>

Phenotypic and genotypic characterization of Vibrio cholerae isolates from a recent cholera outbreak in Senegal: comparison with isolates from Guinea-Bissau
A Aidara, S Koblavi, CS Boye, G Raphenon, et al. 
Am J Trop Med Hyg 1998; 58: 163-167. [PDF]: http://www.ajtmh.org/cgi/reprint/58/2/163>

Categories: Global

World Bank – Health impact of extreme weather events in Sub-Saharan Africa

September 9, 2009 Leave a comment
The health impact of extreme weather events in Sub-Saharan Africa, 2009.
 

Extreme weather events are known to have serious consequences for human health and are predicted to increase in frequency as a result of climate change. Africa is one of the regions that risks being most seriously affected. This paper quantifies the impact of extreme rainfall and temperature events on the incidence of diarrhea, malnutrition and mortality in young children in Sub-Saharan Africa. The panel data set is constructed from Demographic and Health Surveys for 108 regions from 19 Sub-Saharan African countries between 1992 and 2001 and climate data from the Africa Rainfall and Temperature Evaluation System from 1980 to 2001.

 
The results show that both excess rainfall and extreme temperatures significantly raise the incidence of diarrhea and weight-for-height malnutrition among children under the age of three, but have little impact on the long-term health indicators, including height-for-age malnutrition and the under-five mortality rate. The authors use the results to simulate the additional health cost as a proportion of gross domestic product caused by increased climate variability. The projected health cost of increased diarrhea attributable to climate change in 2020 is in the range of 0.2 to 0.5 percent of gross domestic product in Africa. 
Categories: REGIONS

WHO/AFRO – 2009 Cholera Profiles by Country

September 2, 2009 Leave a comment
Categories: Chad, Mali, Mozambique, Zimbabwe

USAID reports on the prevention and control of cholera

August 20, 2009 Leave a comment
Below are links to 23 USAID sponsored reports on cholera. This bibliography will be updated as needed and posted on the Cholera Webliography.

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A Bibliography of USAID Cholera Reports, by Publication Date

 

Categories: Uncategorized Tags: ,

Annotated Cholera Bibliography, January – August 2009

August 18, 2009 Leave a comment

Below are citations and abstracts to 16 journal articles published from January – August 2009. Entries are arranged alphabetically by journal title.

1: Am J Trop Med Hyg. 2009 Apr;80(4):640-5.

Cholera outbreak in Kenyan refugee camp: risk factors for illness and importance of sanitation.

Shultz A, Omollo JO, Burke H, Qassim M, Ochieng JB, Weinberg M, Feikin DR, Breiman RF.

Centers for Disease Control and Prevention, Nairobi and Kisumu, Kenya.

An outbreak of watery diarrhea struck within the Kakuma refugee camp in Kenya in April 2005; 418 people were treated, and 4 persons died. Vibrio cholerae O1 was isolated from 33 patients. In June 2005, we conducted a retrospective matched case-control study to define risk factors associated with cholera among camp residents and identify interventions that could prevent further cases and future outbreaks. We identified cases of cholera through medical records at the main health facility in the camp and matched controls (without watery diarrhea since November 2004) to the cases by age category (< 2, 2-4, 5-14, and > 14 years) and location of residence within the camp. Cases were defined as any person of any age with profuse, effortless watery diarrhea (three or more stools in 24 hours). A multivariate model showed that storing drinking water at home in sealed or covered containers was protective against cholera (matched odds ratio [MOR] = 0.49 [0.25, 0.96]), whereas “sharing a latrine with at least three households” (MOR = 2.17 [1.01, 4.68]) and arriving at the Kakuma camp on or after November 2004 (MOR = 4.66 [1.35, 16.05]) were risk factors. Improving sanitation and promoting methods to ensure safe drinking water are likely to be effective measures in moderating future cholera outbreaks in this setting. Higher risks for cholera illness among refugees recently “in-migrated” suggest that there may be value in targeting new arrivals in the camp for risk reduction messages and interventions, such as covered water storage containers, to prevent cholera.

2: BMC Int Health Hum Rights. 2009 Apr 30;9:8.

Economic burden of cholera in the WHO African region.

Kirigia JM, Sambo LG, Yokouide A, Soumbey-Alley E, Muthuri LK, Kirigia DG.

Health Financing and Social Protection Programme, World Health Organization, Regional Office for Africa, Brazzaville, Congo. kirigiaj@afro.who.int.

BACKGROUND: In 2007, various countries around the world notified 178677 cases of cholera and 4033 cholera deaths to the World Health Organization (WHO). About 62% of those cases and 56.7% of deaths were reported from the WHO African Region alone. To date, no study has been undertaken in the Region to estimate the economic burden of cholera for use in advocacy for its prevention and control. The objective of this study was to estimate the direct and indirect cost of cholera in the WHO African Region.

METHODS: Drawing information from various secondary sources, this study used standard cost-of-illness methods to estimate: (a) the direct costs, i.e. those borne by the health-care system and the family in directly addressing cholera; and (b) the indirect costs, i.e. loss of productivity caused by cholera, which is borne by the individual, the family or
the employer. The study was based on the number of cholera cases and deaths notified to the World Health Organization by countries of the WHO African Region.

RESULTS: The 125018 cases of cholera notified to WHO by countries of the African Region in 2005 resulted in a real total economic loss of US$39 million, US$ 53.2 million and US$64.2 million, assuming a regional life expectancies of 40, 53 and 73 years respectively. The 203,564 cases of cholera notified in 2006 led to a total economic loss US$91.9 million, US$128.1 million and US$156 million, assuming life expectancies of 40, 53 and 73 years respectively. The 110,837 cases of cholera notified in 2007 resulted in an economic loss of US$43.3 million, US$60 million and US$72.7 million, assuming life expectancies of 40, 53 and 73 years respectively. CONCLUSION: There is an urgent need for further research to determine the national-level economic burden of cholera, disaggregated by different productive and social sectors and occupations of patients and relatives, and national-level costs and effectiveness of alternative ways of scaling up population coverage of potable water and clean sanitation facilities.

3: BMC Public Health. 2009 Apr 7;9:99.

Oral cholera vaccine use in Zanzibar: socioeconomic and behavioural features affecting demand and acceptance.

Schaetti C, Hutubessy R, Ali SM, Pach A, Weiss MG, Chaignat CL, Khatib AM.

Department of Public Health and Epidemiology, Swiss Tropical Institute, PO Box, Socinstrasse 57, 4002 Basel, Switzerland. christian.schaetti@unibas.ch

BACKGROUND: Cholera remains a serious public health problem in low-income countries despite efforts in the past to promote oral rehydration therapy as major treatment. In 2007, the majority of worldwide cases (94%) and deaths (99%) were reported from Africa. To improve cholera control efforts in addition to maintaining and improving existing water supply, sanitation and hygiene behaviour measures, the World Health Organization has recently started to consider the use of vaccines as an additional public health tool. To assess this new approach in endemic settings, a project was launched in Zanzibar to vaccinate 50,000 individuals living in communities at high risk of cholera with an oral two-dose vaccine (Dukoral). Immunisation programmes in low-income countries have suffered a reduced coverage or were even brought to a halt because of an ignorance of local realities. To ensure the success of vaccination campaigns, implementers have to consider community-held perceptions and behaviours regarding the infectious disease and the vaccine of interest. The main aim of this study is to provide advice to the Ministry of Health and Social Welfare of Zanzibar regarding routine introduction of an oral cholera vaccine from a socioeconomic and behavioural perspective as part of a long-term development for a sustained cholera prevention strategy.

METHODS AND DESIGN: Qualitative and quantitative methods of health social science research will be applied on four stakeholder levels before and after the mass vaccination campaign. Rapid assessment individual interviews and focus groups will be used to describe cholera- and vaccine-related views of policy makers, health care professionals and community representatives. The cultural epidemiological approach will be employed on the individual household resident level in a repeated cross-sectional design to estimate determinants of anticipated and actual oral cholera vaccine acceptance.

DISCUSSION: The study presented here is designed to inform about people’s perceptions regarding cholera and about socioeconomic and behavioural factors determining anticipated and actual oral cholera vaccine acceptance in Zanzibar. Its pre- and post-intervention design using a mixed-methods approach on different stakeholder levels in communities at high risk of cholera outbreaks will ensure the collection of locally valid data relevant for public health action and planning.

4: Epidemiol Infect. 2009 Jun 19:1-9.

Relationship of cholera incidence to El Niño and solar activity elucidated by time-series analysis.

Ohtomo K, Kobayashi N, Sumi A, Ohtomo N.

Department of Hygiene, Sapporo Medical University School of Medicine, Sapporo, Japan.

Using time-series analysis, we investigated the monthly cholera incidence in Dhaka, Bangladesh during an 18-year period for its relationship to the sea surface temperature (SST) linked to El Niño, and to the sunspot number. Dominant
periodic modes identified for cholera incidence were 11.0, 4.8, 3.5, 2.9, 1.6, 1.0 and 0.5 years. The majority of these modes, e.g. the 11.0-, 4.8-, 3.5-, 1.6- and 1.0-year modes, were essentially consistent with those obtained for the SST
data (dominant modes: 5.1, 3.7, 2.5, 2.1, 1.5, 1.0 years) and the sunspot number data (dominant modes: 22.1, 11.1, 7.3, 4.8, 3.1 years). We confirmed that the variations of cholera incidence were synchronous with SSTs, and were inversely correlated to the sunspot numbers. These results suggest that the cholera incidence in Bangladesh may have been influenced by the occurrence of El Niño and also by the periodic change of solar activity.

5: Epidemiol Infect. 2009 Jun;137(6):906-12.

India – Two sequential outbreaks in two villages illustrate the various modes of transmission of cholera.

DAS A, Manickam P, Hutin Y, Pattanaik B, Pal BB, Chhotray GP, Kar SK, Gupte MD.

National Institute of Epidemiology (ICMR), Chennai, India. dramitav@gmail.com

We investigated two sequential outbreaks of severe diarrhoea in two neighbouring villages of Orissa, in 2005. We conducted descriptive and matched case-control studies. The attack rates were 5.6% (n=62) and 5.2% (n=51), respectively, in the first and second villages. One death was reported in the second village (case fatality 2%). We identified that consumption of milk products prepared in the household of the index case [matched odds ratio (mOR) 5.7, 95% confidence interval (CI) 1.7-30] in the first village, and drinking well water in the second village were associated with the illness (mOR 4.7, 95% CI 1.6-19). We isolated Vibrio cholerae El Tor O1 Ogawa from stool samples from both the villages. Mishandling of milk products led to a cholera outbreak in the first village, which led to sewerage contamination of a well and another outbreak in the second village. Environmental contamination should be expected and prevented during cholera outbreaks.

6: Int J Health Geogr. 2008 Dec 16;7:62.

Spatial dependency of V. cholera prevalence on open space refuse dumps in Kumasi, Ghana: a spatial statistical modelling.

Osei FB, Duker AA.

Department of Geomatic Engineering, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana. oseibadu2004@yahoo.co.uk

BACKGROUND: Cholera has persisted in Ghana since its introduction in the early 70’s. From 1999 to 2005, the Ghana Ministry of Health officially reported a total of 26,924 cases and 620 deaths to the WHO. Etiological studies suggest that the natural habitat of V. cholera is the aquatic environment. Its ability to survive within and outside the aquatic environment makes cholera a complex health problem to manage. Once the disease is introduced in a population, several environmental factors may lead to prolonged transmission and secondary cases. An important environmental factor that predisposes individuals to cholera infection is sanitation. In this study, we exploit the importance of two main spatial measures of sanitation in cholera transmission in an urban city, Kumasi. These are proximity and density of refuse dumps within a community.

RESULTS: A spatial statistical modelling carried out to determine the spatial dependency of cholera prevalence on refuse dumps show that, there is a direct spatial relationship between cholera prevalence and density of refuse dumps, and an inverse spatial relationship between cholera prevalence and distance to refuse dumps. A spatial scan statistics also identified four significant spatial clusters of cholera; a primary cluster with greater than expected cholera prevalence, and three secondary clusters with lower than expected cholera prevalence. A GIS based
buffer analysis also showed that the minimum distance within which refuse dumps should not be sited within community centres is 500 m.

CONCLUSION: The results suggest that proximity and density of open space refuse dumps play a contributory
role in cholera infection in Kumasi.

7: Int J Med Microbiol. 2009 Jun;299(5):367-72.

Cholera in Ethiopia in the 1990 s: epidemiologic patterns, clonal analysis, and antimicrobial resistance.

Scrascia M, Pugliese N, Maimone F, Mohamud KA, Ali IA, Grimont PA, Pazzani C.

Dipartimento di Genetica e Microbiologia, Università di Bari, Via G. Amendola 165/A, 70126 Bari, Italy.

In 1993, after 6 years of absence, cholera re-emerged in the Horn of Africa. Following its introduction to Djibouti, the disease spread to the central and southern areas of Ethiopia reaching Somalia in 1994. Cholera outbreaks persisted
in Ethiopia with a recrudescence of cases in 1998. Twenty-two Vibrio cholerae O1 strains, selected to represent the 1998 history of cholera in Ethiopia, were characterized by random amplified polymorphic DNA patterns, BglI ribotyping and antimicrobial susceptibility. All isolates showed a unique amplified DNA pattern and a prevalent ribotype B8a. All strains were multidrug-resistant and harboured an IncC plasmid which conferred resistance to ampicillin, chloramphenicol, streptomycin, sulfamethoxazole and trimethoprim. These findings indicate that a
group of closely related V. cholerae O1 strains was responsible for the cholera epidemic in Ethiopia in 1998.

8: J Pediatr Gastroenterol Nutr. 2009 Mar;48(3):318-27.

Safety of rapid intravenous rehydration and comparative efficacy of 3 oral rehydration solutions in the treatment of severely malnourished children with dehydrating cholera.

Alam NH, Islam S, Sattar S, Monira S, Desjeux JF.

Clinical Sciences Division, International Centre for Diarrhoeal Disease Research, Dhaka, Bangladesh. nhalam@icddrb.org

OBJECTIVES: Assess the safety of rapid intravenous rehydration of severely malnourished children and compare the efficacy of 3 formulations of oral rehydration salts solutions.

PATIENTS AND METHODS: A group of 175 severely malnourished children of either sex (weight/length <70% of National Center for Health Statistics median), ages 6 to 36 months with cholera, were randomly assigned to receive 1 of 3 oral rehydration solutions (ORSs): glucose-ORS (n=58), glucose-ORS plus 50 g/L of amylase-resistant starch (n=59), or rice-ORS (n=58). Severely dehydrated children at enrollment were administered 100 mL/kg of an intravenous solution for 4 to 6 hours before randomisation, and those with some dehydration were randomised on enrollment. The electrolytes of the 3 ORSs were identical. In acute and convalescence phases, treatment was similar other than the nature of the ORSs.

RESULTS: Intravenous fluid (mean) administered to 149 study children was 103 mL/kg (95% confidence interval [CI] 96-109), and all were rehydrated within 6 hours. None of them developed overhydration or heart failure. During the first 24 hours, stool output (31%; 95% CI 14%-42%; P=0.004) and the ORS intake (26%; 95% CI 12%-37%; P=0.002) of children receiving rice-ORS were significantly less compared with children receiving glucose-ORS. The mean duration of diarrhoea in all children (66 hours; 95% CI 62-71), and time to attain 80% of median weight/length (7.15+/-2.81 days) were not different.

CONCLUSIONS: Dehydration in severely malnourished children can safely be corrected within 6 hours. All study ORSs were equally efficient in correcting dehydration. Rice-ORS significantly reduced the stool output and ORS intake,
confirming previous reports.

9: N Engl J Med. 2009 Mar 12;360(11):1060-3.

A lion in our village–the unconscionable tragedy of cholera in Africa.

Full-text: http://content.nejm.org/cgi/reprint/360/11/1060.pdf

Mintz ED, Guerrant RL.

Diarrheal Diseases Epidemiology Team, Enteric Diseases Epidemiology Branch, Centers for Disease Control and Prevention, Atlanta, USA.

10: PLoS Negl Trop Dis. 2009;3(3):e403.

Immunologic Responses to Vibrio cholerae in Patients Co-Infected with Intestinal Parasites in Bangladesh.

Harris JB, Podolsky MJ, Bhuiyan TR, Chowdhury F, Khan AI, Larocque RC, Logvinenko T, Kendall J, Faruque AS, Nagler CR, Ryan ET, Qadri F, Calderwood SB.

Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, United States of America.

BACKGROUND: Infection with intestinal helminths is common and may contribute to the decreased efficacy of Vibrio cholerae vaccines in endemic compared to non-endemic areas. However, the immunomodulatory effects of concomitant intestinal parasitic infection in cholera patients have not been systematically
evaluated.

METHODS: We evaluated V. cholerae-specific immune responses in a cohort of patients with severe cholera. 361 patients completed 21 days of observation and 53 (15%) had evidence of a concomitant intestinal parasitic infection based on direct microscopy. Although there were no significant differences in the vibriocidal or lipopolysaccharide (LPS)-specific immune responses to V. cholerae, helminth-infected cholera patients had decreased fecal and serum IgA immune responses to the B subunit of cholera toxin (CTB) as well as a more modest decrease in serum IgG response to CTB. These findings remained significant for all classes of helminth infection and when controlling for
potential confounding variables such as age and nutritional status. Although we hypothesized the differential effect on CTB and LPS immune responses was due to T-cell-dependent immunomodulatory effects of helminth infection, we did not find additional evidence to support a classic Th1 or Th2 polarization of the immune response to V. cholerae infection related to parasite infection.

CONCLUSIONS/SIGNIFICANCE: The finding that helminth infection has a profound association with the mucosal humoral immune response to V. cholerae has implications for the development of protective immunity in cholera-endemic areas and provides an additional basis for deworming programs in cholera-endemic areas. Additional studies, including further characterization of the role of T cells in the immune response to human V. cholerae infection and the development of an animal model of co-infection, may provide additional insight into the mechanisms underlying these findings.

11: Pol J Microbiol. 2009;58(1):57-60.

Antibacterial activity of ciprofloxacin and trimethoprim, alone and in combinittion, against Vibrio cholerae O1 biotype El Tor serotype Ogawa isolates.

Mandal S, Pal NK, Chowdhury IH, Debmandal M.

Department of Microbiology, Bacteriology and Serology Unit, Calcutta School of Tropical Medicine, C. R. Avenue, Kolkata-700 073, India. samtropmed@gmail.com

In this communication, the ciprofloxacin-trimethoprim (Cp-Tm) combination showed synergistic (Fractional Inhibitory Concentration, FIC index 0.399) and additive (FIC index 0.665-0.83) effects against Vibrio cholerae O1 biotype El Tor serotype Ogawa isolates having Cp MICs 10 microg/ml and Cp 0.66 microg/ml, respectively, following agar dilution checkerboard method. The time-kill study results demonstrated synergy between Cp and Tm against both groups of isolates providing 2.04 log10 (for strain with Cp MIC 0.66 microg/ml) and 3.12 log10 (for strain with Cp MIC 10 microg/ml) decreases in CFU/ml between the combination and its most active compound. Thus, the findings of the present study suggest an introduction of Cp-Tm combination treatment regimen against drug resistant cholera and this in turn will help in combating the drug resistance of V. cholerae O1 biotype El Tor serotype Ogawa.

12: Soc Sci Med. 2009 Feb;68(4):631-7.

Spatial and environmental connectivity analysis in a cholera vaccine trial.

Emch M, Ali M, Root ED, Yunus M.

Department of Geography, University of North Carolina, Saunders Hall, Campus Box 3220, Chapel Hill, NC 27599-3220, USA. emch@mail.unc.edu

This paper develops theory and methods for vaccine trials that utilize spatial and environmental information. Satellite imagery is used to identify whether households are connected to one another via water bodies in a study area in rural
Bangladesh. Then relationships between neighborhood-level cholera vaccine coverage and placebo incidence and neighborhood-level spatial variables are measured. The study hypothesis is that unvaccinated people who are
environmentally connected to people who have been vaccinated will be at lower risk compared to unvaccinated people who are environmentally connected to people who have not been vaccinated. We use four datasets including: a cholera vaccine trial database, a longitudinal demographic database of the rural population from which the vaccine trial participants were selected, a household-level geographic information system (GIS) database of the same study area, and high resolution Quickbird satellite imagery. An environmental connectivity metric was constructed
by integrating the satellite imagery with the vaccine and demographic databases linked with GIS. The results show that there is a relationship between neighborhood rates of cholera vaccination and placebo incidence. Thus, people are
indirectly protected when more people in their environmentally connected neighborhood are vaccinated. This result is similar to our previous work that used a simpler Euclidean distance neighborhood to measure neighborhood vaccine coverage [Ali, M., Emch, M., von Seidlein, L., Yunus, M., Sack, D. A., Holmgren, J., et al. (2005). Herd immunity conferred by killed oral cholera vaccines in Bangladesh. Lancet, 366(9479), 44-49]. Our new method of measuring environmental connectivity is more precise since it takes into account the transmission mode of cholera and therefore this study validates our assertion that the oral cholera vaccine provides indirect protection in addition to direct protection.

13: Trans R Soc Trop Med Hyg. 2009 May 26.

Effects of local climate variability on transmission dynamics of cholera in Matlab, Bangladesh.

Islam MS, Sharker MA, Rheman S, Hossain S, Mahmud ZH, Islam MS, Uddin AM, Yunus M, Osman MS, Ernst R, Rector I, Larson CP, Luby SP, Endtz HP, Cravioto A.

International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B), GPO Box 128, Dhaka 1000, Bangladesh.

Cholera is considered as a model for climate-related infectious diseases. In Bangladesh, cholera epidemics occur during summer and winter seasons, but it is not known how climate variability influences the seasonality of cholera.
Therefore, the variability pattern of cholera events was studied in relation to the variation in local climate variables in Matlab, Bangladesh. Classification and regression tree (CART) and principal component analysis (PCA) were used to
study the dependency and variability pattern of monthly total cholera cases. An average temperature <23.25 degrees C corresponded to the lowest average cholera occurrence (23 cases/month). At a temperature of >/=23.25 degrees C and sunshine <4.13h/day, the cholera occurrence was 39 cases/month. With increased sunshine (>/=4.13h/day) and temperature (23.25-28.66 degrees C), the second highest cholera occurrence (44 cases/month) was observed. When the sunshine was >/=4.13h/day and the temperature was >28.66 degrees C, the highest cholera occurrence (54 cases/month) was observed. These results demonstrate that in summer and winter seasons in Bangladesh, temperature and sunshine hours compensate each other for higher cholera incidence. The synergistic effect of
temperature and sunshine hours provided the highest number of cholera cases.

14: Trans R Soc Trop Med Hyg. 2009 Mar 5.

A pilot study of faecal volatile organic compounds in faeces from cholera patients in Bangladesh to determine their utility in disease diagnosis.

Garner CE, Smith S, Bardhan PK, Ratcliffe NM, Probert CS.

Clinical Science at South Bristol, Bristol Royal Infirmary, Marlborough Street, Bristol BS2 8HW, UK.

The aim of this pilot study was to analyse the volatile organic compounds in faecal samples collected from cholera patients in Bangladesh to determine biomarkers that could be used for disease diagnosis. Samples were collected from
patients at the International Centre for Diarrhoeal Disease Research, Dhaka, Bangladesh and also from healthy controls at the same institution. The volatile organic compounds were extracted from the headspace above the sample using solid phase microextraction and analysed using gas chromatography-mass spectrometry. A biomarker was identified in the cholera samples that could be used for disease diagnosis.

14: Trans R Soc Trop Med Hyg. 2009 Feb;103(2):137-43.

Influence of temperature and rainfall on the evolution of cholera epidemics in Lusaka, Zambia, 2003-2006: analysis of a time series.

Luque Fernández MA, Bauernfeind A, Jiménez JD, Gil CL, El Omeiri N, Guibert DH.

National Centre of Epidemiology (CNE), Programa de Epidemiología Aplicada de Campo, Instituto de Salud Carlos III, C/Sinesio Delgado 6, Pabellón 12, 28029 Madrid, Spain. fmiguelangel@isciii.es

In this study, we aimed to describe the evolution of three cholera epidemics that occurred in Lusaka, Zambia, between 2003 and 2006 and to analyse the association between the increase in number of cases and climatic factors. A Poisson
autoregressive model controlling for seasonality and trend was built to estimate the association between the increase in the weekly number of cases and weekly means of daily maximum temperature and rainfall. All epidemics showed a seasonal trend coinciding with the rainy season (November to March). A 1 degrees C rise in temperature 6 weeks before the onset of the outbreak explained 5.2% [relative risk (RR) 1.05, 95% CI 1.04-1.06] of the increase in the number of cholera cases (2003-2006). In addition, a 50 mm increase in rainfall 3 weeks before explained an increase of 2.5% (RR 1.02, 95% CI 1.01-1.04). The attributable risks were 4.9% for temperature and 2.4% for rainfall. If 6 weeks prior to the beginning of the rainy season an increase in temperature is observed followed by an increase in rainfall 3 weeks later, both exceeding expected levels, an increase in the number of cases of cholera within the following 3 weeks could be expected. Our explicative model could contribute to developing a warning signal to reduce the impact of a presumed cholera epidemic.

15: Trop Med Int Health. 2009 Jul 17.

Field evaluation of Crystal VC(R) Rapid Dipstick test for cholera during a cholera outbreak in Guinea-Bissau.

Harris JR, Cavallaro EC, de Nóbrega AA, Dos S Barrado JC, Bopp C, Parsons MB, Djalo D, Fonseca FG, Ba U, Semedo A, Sobel J, Mintz ED.

Centers for Disease Control and Prevention, Atlanta, GA, USA

Objectives – To evaluate performance characteristics and ease of use of the new commercially available Crystal VC((R)) Rapid Dipstick (VC) test (Span Diagnostics, India) for Vibrio cholerae O1 and O139.

Methods – Whole stool was collected from patients presenting to a hospital cholera ward during a 2008 epidemic in Guinea-Bissau. The VC test on stool samples was conducted on-site; samples were subsequently stored in Cary-Blair transport media and sent to the Centers for Disease Control and Prevention for diagnostic testing by culture and
polymerase chain reaction (PCR). In addition, four local laboratory technicians who were unfamiliar with the test were provided with stool samples, the VC test kit, and simple written instructions and asked to perform the test and interpret results.

Results – A total of 101 stool specimens were collected and tested. Compared with PCR, the test was 97% sensitive and 71-76% specific. Laboratory technicians in Bissau performed the test and interpreted results correctly using only simple written instructions.

Conclusions – The VC test may be useful for cholera diagnosis in outbreak situations where laboratory capacity is limited.

16: Vaccine. 2009 May 18;27(23):3109-20.

Cost-benefit comparisons of investments in improved water supply and cholera vaccination programs.

Jeuland M, Whittington D.

University of North Carolina at Chapel Hill, Chapel Hill, NC, USA. jeuland@email.unc.edu

This paper presents the first cost-benefit comparison of improved water supply investments and cholera vaccination programs. Specifically, we compare two water supply interventions — deep wells with public hand pumps and biosand filters (an in-house, point-of-use water treatment technology) — with two types of cholera immunization programs with new-generation vaccines — general community-based and targeted and school-based programs. In addition to these four stand-alone investments, we also analyze five combinations of water and vaccine interventions: (1)  borehole+hand pump and community-based cholera vaccination, (2) borehole+hand pump and school-based cholera vaccination, (3) biosand filter and community-based cholera vaccination, (4) biosand filter and school-based cholera vaccination, and (5) biosand filter and borehole+hand pump. Using recent data applicable to developing country locations for parameters such as disease incidence, the effectiveness of vaccine and water supply interventions against
diarrheal diseases, and the value of a statistical life, we construct cost-benefit models for evaluating these  interventions. We then employ probabilistic sensitivity analysis to estimate a frequency distribution of benefit-cost ratios for all four interventions, given a wide variety of possible parameter combinations. Our results demonstrate that there are many plausible conditions in developing countries under which these interventions will be attractive, but that the two improved water supply interventions and the targeted cholera vaccination program are much more likely to yield attractive cost-benefit outcomes than a community-based vaccination program. We show that implementing
community-based cholera vaccination programs after borehole+hand pump or biosand filters have already been installed will rarely be justified. This is especially true when the biosand filters are already in place, because these achieve substantial cholera risk reductions on their own. On the other hand, implementing school-based cholera vaccination programs after the installation of boreholes with hand pump is more likely to be economically attractive. Also, if policymakers were to first invest in cholera vaccinations, then subsequently investing in water interventions is still likely to yield positive economic outcomes. This is because point-of-use water treatment delivers health benefits
other than reduced cholera, and deep boreholes+hand pumps often yield non-health benefits such as time savings. However, cholera vaccination programs are much cheaper than the water supply interventions on a household basis. Donors and governments with limited budgets may thus determine that cholera vaccination programs are more equitable than water supply interventions because more people can receive benefits with a given budget. Practical considerations may also favor cholera vaccination programs in the densely crowded slums of South Asian and
African cities where there may be insufficient space in housing units for some point-of-use technologies, and where non-networked water supply options are limited.

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