ASIATIC CHOLERA
CONTENTS CHAPTER CHAPTER CHOLERA: CURRENT AFRICAN PERSPECTIVES EMERGENCE OF NEW VIRULENCE FACTORS OF VIBRIO CHOLERA AS POTENTIAL VACCINE CANDIDATES METHODS BASED ON BINDING AFFINITY OF THE B-SUBUNIT OF CHOLERA TOXIN TO GANGLIOSIDES IN BIOCHEMISTRY AND HISTOLOGY QUORUM QUENCHING: IMMINENT TARGETS IN VIBRIO CHOLERAE VIBRIO CHOLERAE BIOFILM AND VIRULENCE GENE EXPRESSION THE ENVIRONMENTAL RESERVOIRS AND VECTOR OF VIBRIO CHOLERAE IMPACT OF CLIMATE AND ENVIRONMENTAL FACTORS ON THE EPIDEMIOLOGY OF VIBRIO CHOLERAE IN AQUATIC ECOSYSTEMS SEROGROUPS ARE REPORTED TO BE ASSOCIATED WITH CHOLERA-LIKE EPIDEMICS, IT IS YET TO BE ESTABLISHED WHETHER A DEFINITE SETS OF SEROTYPES OF NON-O1, NON-O139 ARE INTRINSICALLY MORE PATHOGENIC THAN OTHERS FURTHERMORE, THE PATHOGENIC MECHANISMS BY WHICH THESE ENTEROPATHOGENS CAUSE DIARRHOEA ARE NOT YET WELL ESTABLISHED AND THE PATHOGENESIS OF AND O-139 RETAIN THESE GENES, THEY MIGHT PLAY AN IMPORTANT ROLE IN THE EMERGENCE OF NEWER V CHOLEARE PATHOGENS MOST LIKELY DEPENDING ON ASSEMBLING A GROUPING OF GENES FOR BOTH ECOLOGICAL SUITABILITY AND VIRULENCE TO ATTAIN EPIDEMIOLOGICAL PREVALENCE IN ADDITION, A HIGH PROPORTION OF REPORTED V CHOLERAE NON-O1, NON-O139 ISOLATES FROM CLINICAL AND/ENVIRONMENTAL SOURCES ARE MULTIPLE ANTIBIOTIC RESISTANT THUS IT HAS BECOME INCREASINGLY CLEAR THAT THE NON-O1, NON-O139 SEROGROUPS ARE INVOLVED IN THE EMERGENCE OF NEWER VARIANT OF V CHOLERAE THE PRESENT REVIEW WILL FOCUS ON THE CURRENT PERSPECTIVES ON THE DISEASE SPECTRUM, ECOLOGY AND ENVIRONMENTAL STUDIES, VIRULENCE FACTORS AND PATHOGENICITY, BIOCHEMICAL CHARACTERISTICS, DIAGNOSIS AND TREATMENT OF NON-O1, NON-O139, TO CLARIFY THE PUBLIC HEALTH SIGNIFICANCE AND EPIDEMIOLOGICAL POTENTIAL OF V CHOLERAE NON- 1, NON-O139 INFECTIONS INTRODUCTION CHOLERA, ACUTE WATERY DIARRHOEA IS A SERIOUS EPIDEMIC DISEASE CAUSED BY THE TOXIGENIC STRAINS OF A GRAM-NEGATIVE BACTERIUM VIBRIO CHOLERAE CHOLERA MAY HAVE BEEN DERIVED FROM THE GREEK WORDS; CHOLE (BILE) AND REIN (FLOW), MEANING THE FLOW OF BILE IN THAT LANGUAGE THE NATURE OF THE DIARRHOEA IS CHARACTERIZED BY VOLUMINOUS WATERY STOOLS, OFTEN ACCOMPANIED BY VOMITING AND RESULTING IN HYPOVOLEMIC SHOCK AND ACIDOSIS THERE HAS BEEN A SHARP INCREASE IN THE NUMBER OF CHOLERA CASES WORLDWIDE SEVEN DISTINCT PANDEMICS OF CHOLERA HAVE OCCURRED SINCE THE ONSET OF THE FIRST PANDEMIC IN 1817 DURING THE FIFTH PANDEMIC, ROBERT KOCH ISOLATED THE CAUSATIVE ORGANISM OF CHOLERA, REFERRED TO AS ?COMMA BACILLI? FROM RICE WATER STOOLS OF PATIENTS IN EGYPT IN 1883 AND IN INDIA IN 1884 THE PANDEMICS AROSE IN THE INDIAN SUBCONTINENT, USUALLY THE GANGES DELTA, AND SPREAD TO OTHER CONTINENTS EXCEPT FOR THE SEVENTH PANDEMIC, WHICH ORIGINATED ON THE ISLAND OF SULAWESI IN INDONESIA (FARUQUE ET AL , 1998) V CHOLERAE SEROGROUP O1 ARE CLASSIFIED INTO TWO BIOTYPES, EL TOR AND CLASSICAL, ON THE BASIS OF SEVERAL PHENOTYPIC CHARACTERISTICS IN ADDITION V CHOLERAE O1 IS CLASSIFIED INTO TWO SEROTYPES, INABA AND OGAWA, BASED ON AGGLUTINATION IN ANTISERUM A POSSIBLE THIRD SEROTYPE, HIKOJIMA, HAS BEEN DESCRIBED, BUT IT IS VERY RARE SIX PANDEMICS WERE DUE TO CLASSICAL BIOTYPE AND SEVENTH PANDEMIC HAD BEEN CAUSED BY EL TOR BIOTYPE THE SEVENTH PANDEMIC BEGAN IN AND IS CAUSED BY A SPECIFIC CLONE OF EL TOR O1 V CHOLERAE (FARUQUE ET AL , 1998) IN 1991, THE EL TOR O1 SEVENTH PANDEMIC STRAIN WAS INTRODUCED FROM ASIA INTO S AMERICA AND CAUSED A MAJOR CHOLERA EPIDEMIC (WACHSMUTH ET AL , 1993) CURRENTLY, THE EL TOR BIOTYPE IS RESPONSIBLE FOR VIRTUALLY ALL OF THE CHOLERA CASES THROUGHOUT THE WORLD, AND CLASSICAL ISOLATES ARE NOT ENCOUNTERED OUTSIDE OF BANGLADESH OUT OF APPROXIMATELY 206 SEROGROUPS OF V CHOLERAE, ONLY O1 AND O139 ARE THOUGHT TO BE CAPABLE OF CAUSING EPIDEMIC CHOLERA THESE SEROGROUPS CONTAIN GENES FOR CHOLERA TOXIN (CT) AND TOXIN-COREGULATED PILUS (TCP) WITHIN THE O1 AND O139 SEROGROUPS, THE ABILITY TO PRODUCE CT IS A MAJOR DETERMINANT OF VIRULENCE STRAINS BELONGING TO ABOUT 204 OTHER THAN O1 AND O139 SEROGROUPS ARE COLLECTIVELY REFERRED TO AS NON-O1, NON-O139 STRAINS THE MAJORITY OF NON-O1, NON-O139 STRAINS DO NOT CONTAIN GENES ASIATIC CHOLERA ANTIGENS THE PURPOSE OF THE PRESENT REVIEW IS TO PRESENT A CURRENT OVERVIEW OF V CHOLERAE NON-O1, NON-O139 AND TO FOCUS ON CURRENT PERSPECTIVES ON THE DISEASE SPECTRUM, ECOLOGY AND ENVIRONMENTAL STUDIES, VIRULENCE FACTORS AND PATHOGENICITY, BIOCHEMICAL CHARACTERISTICS, DIAGNOSIS, AND TREATMENT OF THESE SEROGROUPS, TO ELUCIDATE THE PUBLIC HEALTH SIGNIFICANCE AND EPIDEMIOLOGICAL POTENTIAL OF V CHOLERAE NON-1, NON-O139 INFECTIONS NON-O1, NON-O139 DISEASE SPECTRUM ALTHOUGH ONLY A MINORITY OF THE STRAINS OF V CHOLERAE NON-O1, NON-O139 SEEMS TO BE ENTEROPATHOGENIC, THESE STRAINS HAVE BEEN RECOGNIZED AS THE CAUSATIVE AGENTS OF SPORADIC CHOLERA-LIKE DISEASE AND OUTBREAKS THE RELATIVE NUMBER OF NON-O1, NON-O139 INFECTIONS IS ON THE INCREASE WORLDWIDE IN 1993, AN EPIDEMIC OF A CHOLERA-LIKE DISEASE OCCURRED IN THAILAND THAT WAS ASSOCIATED WITH NON-O1, NON-O139 (BAGCHI ET AL , 1993) V CHOLERAE NON-O1, NON- O139 STRAINS WERE ISOLATED AS THE CAUSATIVE AGENT OF ACUTE DIARRHOEA FROM THE HOSPITALIZED PATIENTS IN KOLKATA, INDIA (RAMAMURTHY ET AL , 1993) IN 1994, AN OUTBREAK OF DIARRHOEA ASIATIC CHOLERA CAUSED BY NON-O1, NON-O139 OCCURRED AMONG VOLUNTEERS IN A VACCINE TRIAL STUDY AREA IN LIMA, PERU (DALSGAARD ET AL , 1995) CLINICALLY, 95% OF THE PATIENTS PRESENTED WITH WATERY DIARRHOEA WITH EITHER NO OR MILD DEHYDRATION AND ISOLATES RECOVERED FROM DIARRHOEAL PATIENTS BELONGED TO SEVEN DIFFERENT SEROGROUPS, WITH SEROGROUPS O10 (21%) AND O12 (65%) BEING PREDOMINANT MOST OF THESE ISOLATES WERE SUSCEPTIBLE TO A VARIETY OF ANTIMICROBIAL AGENTS THE DISTRIBUTION AND VIRULENCE OF V CHOLERAE NON-O1, NON-O139 IN INDIA BEFORE, DURING AND AFTER THE ADVENT OF O139 SEROGROUP WAS INVESTIGATED (MUKHOPADHYAY ET AL , 1995) A TOTAL OF SEROGROUPS DURING THIS PERIOD (BETWEEN FEBRUARY AND MARCH, 1996) THESE STRAINS WERE FOUND TO BE DEVOID OF THE CTX FILAMENTOUS PHAGE (CTX?) (WALDOR AND MEKALANOS, 1996) AND SOME OTHER VIRULENCE GENES SUCH AS ZOT [ENCODES ZONULA OCCLUDENS TOXIN (ZOT)], ACE [ENCODES ACCESSORY CHOLERA ENTEROTOXIN (ACE)], AND TCPA [ENCODES TOXIN-COREGULATED PILUS SUBUNIT A (TCPA)] GENES ETC (SHARMA ET AL , 1998) SOME STRAINS OF NON-O1, NON-O139 CAN CAUSE CLINICALLY CHOLERA-LIKE DIARRHOEA BY A MECHANISM THAT COULD BE DISTINCT FROM THAT EMPLOYED BY THE TOXIGENIC V CHOLERAE O1 AND O139 STRAINS THE NOMENCLATURE ?ENTEROPATHOGENIC V CHOLERAE’ (EPVC) WAS PROPOSED TO INCLUDE THESE SEROTYPES (SHARMA ET AL , 1998) THE INCIDENCE OF EPVC HAD SHOWN AN UPWARD TREND FROM 1997 THAT CONTINUED INTO 1998 AND IN 1998, THE EPVC STRAINS CONTINUED ONE-THIRD OF THE V CHOLERAE STRAINS ISOLATED FROM HOSPITALIZED PATIENTS IN KOLKATA (GARG ET AL , 1998) SPORADIC CASES OF A SEVERE GASTROENTERITIS ASSOCIATED WITH V CHOLERAE SEROGROUP O141 HAS BEEN REPORTED AND THESE O141 CLINICAL ISOLATES CARRY DNA SEQUENCES THAT HYBRIDIZE TO CHOLERA TOXIN (CT) GENE PROBES (DALSGAARD ET AL , 2001) IN ANOTHER STUDY, THE OCCURRENCE OF V CHOLERAE NON-O1, NON-O139 STRAINS FROM HOSPITALIZED PATIENTS WITH ACUTE DIARRHOEA CONSTITUTED 27 4% (N = 54) OF THE TOTAL 197 V CHOLERAE STRAINS ISOLATED FROM PATIENTS IN KOLKATA, INDIA (CHATTERJEE ET AL , 2009) IN A PREVIOUS STUDY, BETWEEN 1995 AND 2000, MICROBIOLOGICAL RECORDS OF CHILDREN AGED 0-15 YEARS WITH CHOLERA, WHO WERE TREATED AT A HOSPITAL, BANGKOK, THAILAND, WERE RETROSPECTIVELY REVIEWED WITH RESPECT TO THE SEROGROUPS, AND ANTIMICROBIAL SUSCEPTIBILITY OF THE V CHOLERAE ISOLATES (PANCHAROEN ET AL , 2004) OF THE 95 STOOL SPECIMENS THAT WERE POSITIVE FOR V CHOLERAE, O1, AND NON-O1, NON-O139 WERE FOUND IN 52 6% AND 47 4%, RESPECTIVELY THE PREVALENCE AND ANTIMICROBIAL SUSCEPTIBILITIES OF V CHOLERAE O1, O139, AND NON-O1, NON- O139, ISOLATED FROM CHOLERA PATIENTS ADMITTED TO INFECTIOUS DISEASE HOSPITAL, DELHI, INDIA FOR NINE YEARS (1992-2000), WERE ANALYZED TO DETERMINE THE CHANGING TRENDS IN THEIR ISOLATION AND DRUG-RESISTANCE PATTERNS (DAS AND GUPTA, 2005) OF THE 29, 196 STOOL SAMPLES, 13, 730 (47%) WERE POSITIVE FOR V CHOLERAE: 11, 091 FOR V CHOLERAE O1 (80 7%), 1, 943 (14%) FOR V CHOLERAE O139 AND 696 (5%) WERE NON-O1 AND NON-O139 IN RECENT STUDIES, NON-O1, NON- O139 V CHOLERAE HAS BEEN RECOVERED FROM FOOD BORNE DISEASE OUTBREAKS (WEI ET AL , 2008) AND FROM CHILDREN WITH ACUTE DIARRHOEA (GONZÁLEZ ET AL , 2009) ASIATIC CHOLERA (NAMDARI ET AL , 2000) ECOLOGY AND ENVIRONMENTAL STUDIES V CHOLERAE NON-O1, NON-O139 STRAINS ARE UBIQUITOUS IN AQUATIC ENVIRONMENTS (RHODES ET AL , 1986) IN ADDITION, ENVIRONMENTAL NONTOXIGENIC, NON-O1 STRAINS PLAY AN IMPORTANT ROLE IN THE EVOLUTION OF TOXIGENIC V CHOLERAE (KARAOLIS ET AL , 1995) SEVERAL INVESTIGATIONS HAVE INDICATED THE POTENTIAL ECOLOGICAL NICHES WHERE V CHOLERAE THRIVES AND SURVIVES IN AQUATIC ENVIRONMENTS, BUT STILL, THE ECOLOGY OF THIS HUMAN PATHOGEN IS POORLY UNDERSTOOD (COLWELL, 1996; COTTINGHAM ET AL , 2003; WORDEN ET AL , 2006) ADDITIONALLY, V CHOLERAE'S PROLIFERATION AND DYNAMICS IN AQUATIC ENVIRONMENTS ARE NOT WELL UNDERSTOOD V CHOLERAE HAS BEEN SHOWN TO LIVE MAINLY IN ASSOCIATION WITH CRUSTACEAN ZOOPLANKTON (HUQ ET AL , 1983; HEIDELBERG ET AL , ASIATIC CHOLERA