Recurrence of Pelecypod-Associated Cholera in Sardinia

Salmaso, Stefania; Greco, Donato; Bonfiglio, Biagio; Castellani-Pastoris, Maddalena; Felip, Giordano De; Sitzia, Giorgio; Piu, G.; Barra, Lina; Bracciotti, Alessandra; Congiu, Aurelio; Angioni, G.; Zampieri, A; Baine, WilliamB.

doi:10.1016/s0140-6736(80)92553-2

Cited by 32 publications

(12 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Non-O1/non-O139 V. cholerae appears to constitute part of the microflora of prawns (Nair et al 1991) and oysters (McIntyre et al 1979;Salamaso et al 1980). While, non-O1/O139 V. cholerae may be occasionally found in shrimp, there is no known risk of cholera associated with these serotypes in shrimp.…”

Section: Resultsmentioning

confidence: 99%

Detection of ctx gene positive non-O1/non-O139 V. cholerae in shrimp aquaculture environments

Madhusudana

Surendran

2011

J Food Sci Technol

View full text Add to dashboard Cite

Water and post-larvae samples from black tiger (Penaeus monodon) shrimp hatcheries; pond water, pond sediment and shrimp from aquaculture farms were screened for the presence of V. cholerae. A V. cholerae-duplex PCR method was developed by utilizing V. cholerae species specific sodB primers and ctxAB genes specific primers. Incidence of V. cholerae was not observed in shrimp hatchery samples but was noticed in aquaculture samples. The incidence of V. cholerae was higher in pond water (7.6%) than in pond sediment (5.2%). Shrimp head (3.6%) portion had relatively higher incidence than shrimp muscle (1.6%). All the V. cholerae isolates (n=42) belonged to non-O1/non-O139 serogroup, of which 7% of the V. cholerae isolates were potentially cholera-toxigenic (ctx positive). All the ctx positive V. cholerae (n=3) were isolated from the pond water. Since, cholera toxin (CT) is the major contributing factor for cholera gravis, it is proposed that the mere presence of non-O1/non-O139 V. cholerae need not be the biohazard criterion in cultured black tiger shrimp but only the presence of ctx carrying non-O1/non-O139 V. cholerae may be considered as potential public health risk.

show abstract

Section: Resultsmentioning

confidence: 99%

Detection of ctx gene positive non-O1/non-O139 V. cholerae in shrimp aquaculture environments

Madhusudana

Surendran

2011

J Food Sci Technol

View full text Add to dashboard Cite

show abstract

“…Cholera is confined to humans and is thought to be a relatively recent disease which was unknown to nomadic Palaeolithic humans but which developed when villages and village water supplies were established (15). However, V. cholerae is a species commonly found in marine and estuarine environments (46) and is also found closely associated with prawns (31) and oysters (2,4,28,47). It appears from our data that the pathogenic forms must have arisen independently from such environmental forms.…”

Section: Discussionmentioning

confidence: 99%

“…Biochemically, it is nearly impossible to distinguish O1 and non-O1 V. cholerae (10,38). V. cholerae non-O1 strains are far more frequently isolated from environmental sources than O1 strains and appear to constitute part of the normal microflora of prawns (31) and oysters (2,4,28,47). Most environmental isolates do not possess cholera toxin genes, a heat-stable enterotoxin (31,32), or toxin coregulated pilus (49,54).…”

mentioning

confidence: 99%

The sixth and seventh cholera pandemics are due to independent clones separately derived from environmental, nontoxigenic, non-O1 Vibrio cholerae

1995

View full text Add to dashboard Cite

The DNA sequences of the asd genes from 45 isolates of Vibrio cholerae (19 clinical O1 isolates, 2 environmental nontoxigenic O1 isolates, and 24 isolates with different non-O1 antigens) were determined. No differences were found within either sixth-or seventh-pandemic isolates; however, variation was found between the two forms and among the non-O1 isolates. O139 isolates had sequences identical to those of seventh-pandemic isolates. Phylogenetic trees with Vibrio mimicus as the outgroup suggest that the sixth-pandemic, seventhpandemic, and U.S. Gulf isolates are three clones that have evolved independently from different lineages of environmental, nontoxigenic, non-O1 V. cholerae isolates. There is evidence for horizontal transfer of O antigen, since isolates with nearly identical asd sequences had different O antigens, and isolates with the O1 antigen did not cluster together but were found in different lineages. We also found evidence for recombination events within the asd gene of V. cholerae. V. cholerae may have a higher level of genetic exchange and a lower level of clonality than species such as Salmonella enterica and Escherichia coli.Vibrio cholerae is a normal inhabitant of aquatic environments (46). However, contaminated water supplies in some areas of the world have enabled some clones of the species to become pathogenic for humans. Seven pandemics of cholera have been recorded previously (12,36). The seventh pandemic, beginning in 1961, is clonal (20,22,24,37), is well defined, and has a known starting date, and previous studies (7,22,24,37,53) have shown it to have accumulated variation, with both random genetic drift and recombination possibly being involved. There are 140 known serotypes of V. cholerae (50). Until recently, all recorded pandemic and epidemic cases of cholera have been associated with the type O1 antigen; however, an epidemic which began in India late in 1992 and spread to several neighboring countries is caused by an O139 strain (1,8,33,39). Studies have shown that the O139 strain is genetically very similar to strains of the seventh pandemic (13,22,37,54). Karaolis et al. (22) have further shown that O139 isolates appear to have evolved from early seventh-pandemic isolates. Biochemically, it is nearly impossible to distinguish O1 and non-O1 V. cholerae (10,38). V. cholerae non-O1 strains are far more frequently isolated from environmental sources than O1 strains and appear to constitute part of the normal microflora of prawns (31) and oysters (2,4,28,47). Most environmental isolates do not possess cholera toxin genes, a heat-stable enterotoxin (31, 32), or toxin coregulated pilus (49, 54).The population structure and molecular evolution of V. cholerae as a species have not been well characterized, and the relationship of the sixth-and seventh-pandemic isolates is not clear. We have investigated sequence variation within V. cholerae by examining variation in the asd locus, one of the few V. cholerae chromosomal housekeeping genes sequenced to date. Housekeeping genes are conce...

show abstract

“…The chitinous surface of the crustaceans provides a suitable substrate for reproduction of the pathogenic microbe. Epidemiologic studies (47)(48)(49) revealed an association between the incidence of cholera and the consumption of fish and other raw or undercooked seafood.…”

Section: Phytoplankton and Zooplanktonmentioning

confidence: 99%

Ecology of Vibrio cholerae serogroup 01 in aquatic environments

Borroto¹

1997

Rev Panam Salud Publica

View full text Add to dashboard Cite

The endemic and seasonal nature of cholera depends upon the survival of Vibrio cholerae 01 in a viable but not necessarily culturable state in ecologic niches in aquatic environments during interepidemic periods. To understand the ecology of V. cholerae it is necessary to know which aquatic ecosystems can harbor it and thus contribute to the endemic presence of cholera in Latin America. This article summarizes knowledge about the ecology of V. cholerae 01, specifically, the abiotic and biotic factors that are relevant to the microbe's survival in aquatic environments. This pathogen finds favorable conditions in waters characterized by moderate salinity, high nutrient content, warm temperature, neutral or slightly alkaline pH, and the presence of aquatic macrophytes, phytoplankton, zooplankton, fish, mollusks, and crustaceans. These ecologic conditions are typical of estuaries and coastal swamps, and toxigenic V. cholerae 01 is now considered an autochthonous member of the microbial flora of these environments. The microorganism has also shown the ability to colonize freshwater ecosystems in its viable but not necessarily culturable form, if organic or inorganic substrates that favor its survival are available. ABSTRACTVibrio cholerae serogroup 01 consists of the classic and El Tor biotypes, the latter of which is responsible for the seventh cholera pandemic, which is now in progress. These two biotypes comprise the Inaba, Ogawa, and Hikojima serotypes. Epidemic cholera is caused by strains of V. cholerae that produce enterotoxin; strains that do not produce the toxin are identified as nonepidemic, although they may cause diarrhea. Vibrios that do not agglutinate serogroup 01 antiserum,

show abstract

Recurrence of Pelecypod-Associated Cholera in Sardinia

Cited by 32 publications

References 11 publications

Detection of ctx gene positive non-O1/non-O139 V. cholerae in shrimp aquaculture environments

Detection of ctx gene positive non-O1/non-O139 V. cholerae in shrimp aquaculture environments

The sixth and seventh cholera pandemics are due to independent clones separately derived from environmental, nontoxigenic, non-O1 Vibrio cholerae

Ecology of Vibrio cholerae serogroup 01 in aquatic environments

Contact Info

Product

Resources

About