Role of household animals in maintenance of cholera infection in a community

When Vibrios Take Flight: A Meta-Analysis of Pathogenic Vibrio Species in Wild and Domestic Birds

Of the over 100 species in the genus Vibrio, approximately twelve are associated with clinical disease, such as cholera and vibriosis. Crucially, eleven of those twelve, including Vibrio cholerae and Vibrio vulnificus, have been isolated from birds. Since 1965, pathogenic Vibrio species have been consistently isolated from aquatic and ground-foraging bird species, which has implications for public health, as well as the One Health paradigm defined as an ecology-inspired, integrative framework for the study of health and disease, inclusive of environmental, human, and animal health. In this meta-analysis, we identified 76 studies from the primary literature which report on or examine birds as hosts for pathogenic Vibrio species. We found that the burden of disease in birds was most commonly associated with V. cholerae, followed by V. metschnikovii and V. parahaemolyticus. Meta-analysis wide prevalence of our Vibrio pathogens varied from 19% for V. parahaemolyticus to 1% for V. mimicus. Wild and domestic birds were both affected, which may have implications for conservation, as well as agriculturally associated avian species. As pathogenic Vibrios become more abundant throughout the world as a result of warming estuaries and oceans, susceptible avian species should be continually monitored as potential reservoirs for these pathogens.

Zoonotic Bacteria in Anolis sp., an Invasive Species Introduced to the Canary Islands (Spain)

Lizards belonging to the genus Anolis are native to America and have been introduced in many parts of the world. In this work, a gastrointestinal microbiological analysis from Anolis sp. introduced to Tenerife, Canary Island, was carried out. A total of 74 individuals were analyzed by culture and molecular tools. Pseudomonas spp. was the most prevalent bacteria isolated (64.3%), followed by enteropathogenic Escherichia coli with at least one of the investigated virulent genes (stx1, stx2, and eae) (44.6%). The stx2 gene was more prevalent which differs to that reported in other reptiles, probably due to wastewater transmission. Campylobacter spp. was detected in 32.4% of the animals, highlighting the detection of C. jejuni and C. fetus by their relevance to public health. The zoonotic Staphylococcus lugdunensis, found in 14.9% of the animals, was firstly detected in reptiles. Vibrio sp. which is more associated with aquatic environments was found in 10.8% of the lizards in this study, with Vibrio cholerae being found in two of the animals. The prevalence of Salmonella sp. (5.4%) was low, compared with other studies carried out in reptiles. These results indicate that Anolis sp. in Tenerife could be playing a role in the maintenance and spread of the pathogens detected, being a possible risk factor for public health and biodiversity conservation.

Meat‐Adaptive Genes and the Evolution of Slower Aging in Humans

The chimpanzee life span is shorter than that of humans, which is consistent with a faster schedule of aging. We consider aspects of diet that may have selected for genes that allowed the evolution of longer human life spans with slower aging. Diet has changed remarkably during human evolution. All direct human ancestors are believed to have been largely herbivorous. Chimpanzees eat more meat than other great apes, but in captivity are sensitive to hypercholesterolemia and vascular disease. We argue that this dietary shift to increased regular consumption of fatty animal tissues in the course of hominid evolution was mediated by selection for "meat-adaptive" genes. This selection conferred resistance to disease risks associated with meat eating also increased life expectancy. One candidate gene is apolipoprotein E (apoE), with the E3 allele evolved in the genus Homo that reduces the risks for Alzheimer's and vascular disease, as well as influencing inflammation, infection, and neuronal growth. Other evolved genes mediate lipid metabolism and host defense. The timing of the evolution of apoE and other candidates for meat-adaptive genes is discussed in relation to key events in human evolution.

Characterization of Vibrio cgolerae non-O1 serogroups obtained from an outbreak of diarrhea in Lima, Peru

In February 1994, an outbreak of diarrhea caused by non-O1 Vibrio cholerae occurred among volunteers in a vaccine trial study area in Lima, Peru. Clinically, 95% of the patients presented with liquid diarrhea with either no or mild dehydration. Serogrouping of 58 isolates recovered from diarrheal patients affected in the outbreak revealed seven different serogroups, with serogroups O10 (21%) and O12 (65%) being predominant. Most of these isolates were susceptible to a variety of antimicrobial agents. None of the 58 isolates hybridized with a DNA probe previously used to detect the gene encoding the heat-stable enterotoxin NAG-ST or produced cholera toxin as assessed by GM1 ganglioside enzyme-linked immunosorbent assay. Ribotyping exhibited 10 different BglI ribotype patterns among the 58 V. cholera non-O1 strains studied. However, ribotyping showed that all isolates belonging to serogroup O12 exhibited identical ribotypes and that 83% of the serogroup O10 isolates belonged to another identical ribotype, thus showing excellent correlation between ribotypes and serogroups. Among a group of O10 and O12 isolates selected for virulence studies, none produced enterotoxin whereas the majority produced a cytotoxin, as assessed in Y1 and HeLa cells. These isolates were also negative for the gene encoding zonula occludens toxin (Zot) as assessed by a PCR assay. The isolates tested showed strong adherence and some degree of invasion in the HEp-2 cell assay, whereas none of the isolates was positive in the PCR assay for the gene encoding the toxin coregulated pilus subunit A antigen (tcpA). In the removable intestinal tie adult rabbit diarrhea model, O10 and O12 serogroup isolates produced severe diarrhea and occasionally death when rabbits were challenged with 10(10) bacterial cells. Fluid accumulation was shown in the rabbit intestinal loop test when whole cultures were injected. No significant difference in virulence was shown between serogroup O10 and O12 isolates. This study provides further evidence that V. chlorae non-O1 non-O139 strains have diarrhegenic potential for humans through a yet-undefined mechanism(s) and that such strains can cause outbreaks.

Epidemic of diarrhea caused by Vibrio cholerae non-O1 that produced heat-stable toxin among Khmers in a camp in Thailand

An epidemic of a cholera-like disease occurred among Khmers in a camp in Aranyaprathet, Thailand, in May 1990. Of 215 patients with diarrhea, Vibrio cholerae O1 was isolated from 25 (12%) and V. cholerae non-O1 was isolated from 15 (7%). Five of 15 (33%) non-O1 V. cholerae isolates hybridized with two different oligonucleotide probes previously used to detect V. cholerae non-O1 that produces a heat-stable toxin. This is the first description of an epidemic of diarrhea caused by V. cholerae non-O1 that produces heat-stable toxin.

Toxigenic Vibrio cholerae non-O:1 isolated from a goat in The Netherlands

A case of enterotoxicosis in a goat at necropsy is described. The animal had died without clinical signs. Toxigenic Vibrio cholerae non-O:1 was isolated from the intestines. This species has not been reported earlier from healthy or diseased farm animals, such as goats, in the Netherlands.

The human pathogenic vibrios--a public health update with environmental perspectives

Pathogenic Vibrio species are naturally-occurring bacteria in freshwater and saline aquatic environments. Counts of free-living bacteria in water are generally less than required to induce disease. Increases in number of organisms towards an infective dose can occur as water temperatures rise seasonally followed by growth and concentration of bacteria on higher animals, such as chitinous plankton, or accumulation by shellfish and seafood. Pathogenic Vibrio species must elaborate a series of virulence factors to elicit disease in humans. Activities which predispose diarrhoeal and extraintestinal infections include ingestion of seafood and shellfish and occupational or recreational exposure to natural aquatic environments, especially those above 20 degrees C. Travel to areas endemic for diseases due to pathogenic Vibrio species may be associated with infections. Host risk factors strongly associated with infections are lack of gastric acid and liver disorders. Involvement of pathogenic Vibrio species in cases of diarrhoea should be suspected especially if infection is associated with ingestion of seafood or shellfish, raw or undercooked, in the previous 72 h. Vibrio species should be suspected in any acute infection associated with wounds sustained or exposed in the marine or estuarine environment. Laboratories serving coastal areas where infection due to pathogenic Vibrio species are most likely to occur should consider routine use of TCBS agar and other detection regimens for culture of Vibrio species from faeces, blood and samples from wound and ear infections.

Behavior of Vibrio cholerae in hot foods

Four food types held hot at 45 to 60 degrees C were deliberately contaminated with O1 and non-O1 Vibrio cholerae strains. These organisms were assayed for survival and recovery from the foods within 1 h of the time the food was kept hot. The results showed no growth of V. cholerae non-O1 on thiosulfate-citrate bile-sucrose agar plates after 24 h of incubation at 37 degrees C for food held hot at 50 to 60 degrees C. Growth was low for V. cholerae O1 and was not achieved in some instances in which foods were held at either 55 or 60 degrees C after 40 or 60 min of from the time the food was kept hot. Both organisms, however, were recovered equally from all food types held at all temperatures after 48 h of incubation. When incubated for an additional 24 h, the organisms grew to unusually small-sized colonies, measuring 0.1 to 0.3 mm in diameter, on the same agar plates that were negative for growth after an initial 24 h of incubation. It was concluded that V. cholerae survived the period of time held at hot temperatures. Although the organisms were not recovered from some foods when held at some of the temperatures and times after 24 h of incubation, they remained viable. An incubation period of 48 h at 37 degrees C was found to be appropriate for the recovery of V. cholerae from hot foods.

Investigation of cholera acquired from the riverine environment in Queensland

Since February 1977, five patients with cholera apparently acquired the infection from the riverine environment in Queensland. A total of 13 rivers have now yielded at least one isolate of Vibrio cholerae 01 biovar El Tor. Investigations indicate that the organism, including toxigenic strains, can survive and multiply in the riverine environment. No human or animal reservoirs and no ecological niches were identified and no route of importation or dissemination of the organism was discovered. The microbiological examination of faeces in all medical laboratories in Australia should include methods for detecting the cholera organism as a routine. When confronted with a cholera infection, medical practitioners should obtain a history of recent travel, both in Australia and overseas.

Isolation of non-O1 Vibrio cholerae associated with enteric disease of herbivores in western Colorado

Non-O1 Vibrio cholerae was isolated from a horse (Equus caballus), a lamb (genus Ovis), and two American buffalo (Bison bison) suffering from enteric disease in the western part of Colorado. In 1981, a foal died of apparent respiratory failure. Necropsy findings included heart failure and gastroenteritis. V. cholerae serovar 347 (Smith) was isolated from the colon of this animal. V. cholerae serovar 27 (Smith) was isolated in 1983 from the intestine of a feedlot lamb suffering from pneumonia and severe watery diarrhea. In 1984, an enteric disease occurred in a herd of American bison. The sick animals were depressed and separated from the herd, dying in about 3 days. Of approximately 100 adult bison, 7 died. Necropsy of one animal revealed that gross lesions were limited to the gastrointestinal tract. V. cholerae serovar 27 (Smith) was isolated from the abomasum, duodenum, and colon of this animal. A swab specimen from the intestine of another dead bison also yielded V. cholerae serovar 27 (Smith).

Response of toxigenic Vibrio cholerae 01 to physico-chemical stresses in aquatic environments

The survival and growth of toxigenic Vibrio cholerae 01 in water under various conditions of salinity, pH, temperature and cation composition and concentration were studied in an extensive series of laboratory experiments. Inter- and intra-strain variation in stress response (of 01 and non-01 strains) and the ability of V. cholerae to adapt to stressful environments were also studied. Toxigenic V. cholerae 01 were able to survive for at least 70 days at 25 degrees C in solutions of sea salt. The optimal salt concentration was 2.0% though all solutions in the range 0.25-3.0% gave good support. Substrains with enhanced capacity to persist at sub-optimal salinity (0.1%) were demonstrated. A great degree of inter-strain variation in stress response at low salinity (0.05%) was found among 59 strains, and this variation was unrelated to serogroup (01 or non-01), source (clinical or environmental) or country of origin (Tanzania or Bangladesh). At optimal salinity, inter-strain variation was less and 18 out of 20 strains remained viable at high concentrations for at least 40 months at 25 degrees C. V. cholerae 01 could not survive beyond 45 days at 4 degrees C and optimal salinity, either with or without nutrients. The optimal pH range for survival at 25 degrees C was 7.0-8.5 at optimal salinity, and 7.5-9.0 at low salinity. V. cholerae 01 require Na+ for survival in the absence of nutrients, and for enhanced growth in their presence. The presence of Ca2+ or Mg2+, in addition to Na+, further enhanced survival. These, and other results reported in this paper, suggest that toxigenic V. cholerae 01 are able to survive for extended periods in warm water containing no nutrients but having a salinity of 0.25-3.0% and a pH of around 8.0. With added nutrients and under the same conditions, rapid growth is possible. The implications of these findings for the identification of putative aquatic reservoirs of V. cholerae 01, and for the epidemiology of cholera, are considerable.

Prevalence of non-cholera vibrios in cavum nasi and pharynx of ducks

Investigations among ducks on ten different farms showed a high prevalence of Vibrio cholerae in cavum nasi and Pharynx after the ducks were admitted to the open field. In no case was Vibrio cholerae isolated from ducks which had never been outside the houses. At least six serovars were isolated, 0:54 being the most prevalent. All the strains isolated produced a distinctive cytotoxic effect in YI adrenal cells and caused fluid accumulation in rabbit gut loops. Migratory birds were incriminated as the source of initial contamination.