National Enteric Disease Surveillance: COVIS Annual Summary, 2014

CS265270-A May 2016

National Enteric Disease Surveillance:

COVIS Annual Summary, 2014

Summary of Human Vibrio Cases Reported to CDC, 2014

The Cholera and Other Vibrio Illness Surveillance (COVIS) system is a national surveillance system for human

infection with pathogenic species of the family Vibrionaceae, which cause vibriosis and cholera. The Centers for

Disease Control and Prevention (CDC) maintains COVIS. Information from COVIS helps track Vibrio infections and

determine host, food, and environmental risk factors for these infections.

CDC initiated COVIS in collaboration with the Food and Drug Administration and four Gulf Coast states

(Alabama, Florida, Louisiana, and Texas) in 1989. Using the COVIS report form (available at http://www.cdc.gov/

nationalsurveillance/PDFs/CDC5279_COVISvibriosis.pdf), participating health officials report cases of vibriosis

and cholera. The case report includes clinical data, including information about underlying illness; detailed history

of seafood consumption; detailed history of exposure to bodies of water, raw or live seafood or their drippings, or

contact with marine life in the seven days before illness onset; and traceback information on implicated seafood.

Before 2007, only cholera, which by definition is caused by infection with toxigenic Vibrio cholerae serogroup

O1 or O139, was nationally notifiable. In January 2007, infection with other serogroups of V. cholerae and other

species from the family Vibrionaceae also became nationally notifiable, as vibriosis.

For cholera, CDC requests that all state health departments send all Vibrio cholerae, Vibrio mimicus, and isolates

from known or suspected outbreaks to CDC for additional characterization. For V. cholerae, CDC identifies

serogroups O1, O75, O139, and O141 and determines whether the isolate produces cholera toxin. For V. cholerae

isolates that are found to be toxigenic, CDC conducts antimicrobial susceptibility testing and pulsed-field gel

electrophoresis (PFGE).

For vibriosis, CDC accepts isolates for identification, subtyping, and antimicrobial resistance testing. Although

all Vibrio infections are nationally notifiable, many cases are likely not recognized because Vibrios are not easily

identified on routine enteric media. A selective medium, such as thiosulfate citrate bile salts sucrose agar (TCBS),

should be used. More information on Vibrio and Vibrio cholerae testing at CDC can be found in the enteric diseases

isolate submission memo and table available at http://www.cdc.gov/ncezid/dfwed/edlb/additional.html.

This report summarizes human Vibrio infections occurring during 2014 reported to COVIS. Results are presented

in two categories: (1) infection with pathogenic species of the family Vibrionaceae (other than toxigenic Vibrio

cholerae serogroups O1 and O139), which cause vibriosis; this category includes infection with toxigenic V.

cholerae of serogroups other than O1 and O139, and (2) infection with toxigenic V. cholerae serogroups O1

and O139, which cause cholera. Whereas many Vibrio species are well-recognized human pathogens, the

status of some species (including Photobacterium damselae subsp. damselae (formerly V. damsela), V. furnissii, V.

metschnikovii, and V. cincinnatiensis) as human enteric or wound pathogens is less clear.

Understanding the routes by which infection is transmitted is essential for control. For vibriosis, cases are

summarized by place of exposure (travel-associated vs. domestically acquired). Travel-associated cases are

defined as infections in persons who reported international travel in the seven days before illness began; all other

infections are defined as domestically acquired cases. For domestically acquired vibriosis, transmission routes

(foodborne, non-foodborne, and unknown) are determined based on reported patient exposures and specimen

sites (see Appendix for classification method). For toxigenic V. cholerae (all serogroups), exposures are summarized

by place of exposure (travel-associated vs. domestically acquired) and then, if information is available, by source

(such as consumption of contaminated seafood).

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I. Vibriosis

Pathogenic species of the family Vibrionaceae (excluding toxigenic V. cholerae O1 and O139)

In 2014, 1,252 Vibrio infections (excluding toxigenic V. cholerae O1 and O139) were reported to COVIS (Table 1).

Among patients for whom information was available, 326 (27%) of were hospitalized, and 34 (4%) of died. The

most frequently reported single species was V. parahaemolyticus, which was isolated from 605 (48%) of patients.

Of the patients infected with V. parahaemolyticus for whom information was available, 86 (15%) were hospitalized,

and 4 (1%) died. V. alginolyticus was isolated from 239 (19%) of the patients; of the patients for whom information

was available, 32 (14%) were hospitalized; none died. V. vulnificus was isolated from 124 (10%) of the patients; of

the patients for whom information was available, 97 (79%) were hospitalized, and 21 (18%) died.

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Table 1. Vibriosis cases by species, selected patient demographic characteristics, and outcomes,

United States, 2014.

Demographic Characteristics Outcomes

Genus and Species of

Vibrionaceae

Cases Age (years) Sex Hospitalizations Deaths

N % Median Range

Male

(n / N)

% n / N % n / N %

V. parahaemolyticus 605 48 47 4 – 96 396 / 603 66 86 / 575 15 4 / 389 1

V. alginolyticus 239 19 36.5 2 – 91 176 / 239 74 32 / 222 14 0 / 180 0

V. vulniﬁcus 124 10 59.5 10 – 93 101 / 124 81 97 / 123 79 21 / 117 18

V. cholerae (excluding toxigenic

O1 and O139)*

80 6 50.5 3 – 90 54 / 80 68 36 / 79 46 3 / 65 5

V. ﬂuvialis 71 6 59.5 6 – 91 43 / 71 61 26 / 70 37 1 / 61 2

V. mimicus 31 2 53 0 – 90 16 / 30 53 17 / 30 57 1 / 31 3

Grimontia hollisae (formerly V.

hollisae)

10 <1 47 24 – 71 9 / 10 90 4 / 10 40 0 / 9 0

Photobacterium damselae subsp.

damselae (formerly V. damsela)

6 <1 56.5 20 – 76 4 / 6 67 1 / 5 20 0 / 6 0

V. harveyi 4 <1 53.5 21 – 83 3 / 4 75 0 / 4 0 0 / 4 0

V. metschnikovii 3 <1 53 50 – 69 1 / 3 33 0 / 2 0 0 / 3 0

V. furnissii 1 <1 79 79 – 79 1 / 1 100 0 / 1 0 0 / 1 0

V. metoecus 1 <1 54 54 – 54 0 / 1 0 0 / 1 0 0 / 1 0

V. navarrensis 1 <1 7 7 – 7 0 / 1 0 0 / 1 0 0 / 1 0

Species not identiﬁed 52 4 44 3 – 86 36 / 52 69 11 / 47 23 0 / 41 0

Multiple species

†

24 2 50 3 – 72 11 / 24 46 16 / 23 70 4 / 22 18

Total 1,252 100 48 0 – 96 851 / 1249 68 326 / 1193 27 34 / 931 4

*Includes non-toxigenic V. cholerae non-O1, non-O139 (78 cases) and O1 (2 cases).

†The following combinations of Vibrio species were isolated from patients infected with multiple species: V. alginolyticus, V. parahaemolyticus (4 patients); V.

fluvialis, V. parahaemolyticus (2 patients); V. mimicus, V. fluvialis (1 patient); V. cholerae non-O1, non-O139, V. parahaemolyticus (3 patients); V. cholerae non-O1,

non-O139, Vibrio species not identified (2 patients); V. fluvialis, V. vulnificus (1 patient); V. parahaemolyticus, V. vulnificus (5 patients); V. parahaemolyticus,

Vibrio species not identified (1 patient); V. alginolyticus, Vibrio species not identified (1 patient); V. vulnificus, Vibrio species not identified (1 patient); V.

alginolyticus, V. vulnificus (2 patients); V. mimicus, V. cholerae serogroup not specified (1 patient). None of these are included in the rows for individual

species.

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Geographic Location

Of the 1,252 vibriosis cases, 325 (26%) were reported from Gulf Coast states, 425 (34%) from Pacific Coast states,

325 (26%) from Atlantic Coast states, and 177 (14%) from non-coastal states (Figure 1).

The Vibrio species reported most frequently from Gulf Coast states were V. alginolyticus 91 (28%), V. vulnificus 64

(21%), and V. parahaemolyticus 62 (20%). The Vibrio species reported most frequently from non-Gulf Coast states

were V. parahaemolyticus 543 (59%), V. alginolyticus 148 (16%), and V. vulnificus 60 (7%).

Figure 1. Number of cases of Vibrio infections (excluding toxigenic V. cholerae O1 and O139), by

state, 2014 (N=1,252 from 46 states and the District of Columbia).

Region

Atlantic

Gulf

Non-coastal

Paciﬁc

268

DE-5

DC-1

CT-13

168

MD-39

MA-42

NJ-32

RI-6

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Transmission categories and reported exposures

Of 1,252 vibriosis patients, 89 (7%) reported international travel in the seven days before illness began. Of 1,163

domestically acquired vibriosis cases, 655 (56%) were classified as confirmed or probable foodborne, 402 (35%) as

confirmed or probable non-foodborne, and 106 (9%) as having an unknown transmission route (Figure 2). Illnesses

peaked in the summer months for all categories, but the peak was most pronounced for foodborne infections

(Figure 3).

Among patients with confirmed and probable foodborne vibriosis who reported eating a single seafood item

(Table 2), 196 (69%) ate oysters (89% of whom consumed them raw), 12 (4%) ate clams (83% of whom consumed

them raw), 16 (6%) ate crab, and 29 (10%) ate finfish.

Among patients with confirmed or probable non-foodborne transmission, 316 (79%) reported having skin

exposure to a body of water within 7 days before illness began, 67 (17%) reported contact with marine wildlife,

and 69 (17%) reported handling seafood.

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Figure 2. Domestically acquired vibriosis cases by transmission route and species, United States,

2014 (N=1,163).

V. parahaemolyticus (n=552)

V. alginolyticus (n=228)

V. vulniﬁcus (n=119)

V. ﬂuvialis (n=68)

V. cholerae (n=66)

V. mimicus (n=31)

G. hollisae (n=10)

V. metoecus (n=1)

P. damselae subsp. damselae (n=6)

V. furnissii (n=1)

V. harveyi (n=3)

V. navarrensis (n=1)

Species not identified (n=50)

Multiple species (n=24)

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

Confirmed Foodborne Probable Foodbornev Confirmed Non-foodborne Probable Non-foodborne Unknown

V. metschnikovii (n=3)

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100

120

140

160

180

200

Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec

No. of cases

Month of illness onset

Total confirmed and probable foodborne Total confirmed and probable non-foodborne Unknown

Figure 3. Domestically acquired vibriosis cases, by month of illness onset or specimen collection

(when onset date not available), and transmission route, United States, 2014 (N=1,162*).

Table 2. Seafood exposures among 286 patients with domestically acquired foodborne

vibriosis* who reported eating a single seafood item in the week before illness onset, United

States, 2014.

Mollusks Crustaceans Other

Oysters Clams Mussels Shrimp Lobster Crab Crayfish

Other

Shellfish**

Finfish

†

Patients who ate single

seafood item, n (% of 286)

196 (69) 12 (4) 3 (1) 16 (6) 3 (1) 16 (6) 5 (2) 7 (2) 29 (10)

Patients who ate the single

seafood item raw,

n (% of n in row above)

174 (89) 10 (83) 0 (0) 2 (13) 0 (0) 1 (6) 0 (0) 2 (29) 5 (17)

*Includes confirmed and probable foodborne cases.

**Other shellfish reported: conch, scallops.

†

Finfish reported: bass, bluegill, catfish, cod, flounder, herring, poke, salmon, squid, tilapia, tuna, walrus, and white fish.

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Toxigenic V. cholerae, excluding serogroups O1 and O139

In 2014, no patients with non-O1, non-O139 toxigenic V. cholerae infection were reported.

II. Cholera

Serogroups O1 & O139

In 2014, 7 patients with toxigenic V. cholerae serogroup O1 infection were reported. Of the 7 patients, 57% were

hospitalized and none died. All cases were travel-associated (2 with travel to Cuba, 2 to Ghana, and 3 to other

cholera-affected countries).

No cases of toxigenic V. cholerae O139 infection were reported.

Table 3. Cases of toxigenic V. cholerae serogroup O1, biotype El Tor infection, 2014.

Location Age Sex

Month of

Illness Onset

International

Travel

Exposure Serotype

Antimicrobial

Resistance*

Florida 59 F February Yes Travel to Cuba Ogawa STR, SOX, NAL, STX

Florida 2 M March Yes Travel to Cuba Ogawa FUR, STR, SOX, NAL, STX

Arkansas 57 M August Yes Resident of Ghana Ogawa FUR, STR, SOX, NAL, STX

Minnesota 38 M August Yes Travel to India Ogawa FUR, NAL

Massachusetts 57 M August Yes Travel to Ghana Ogawa FUR, STR, SOX, NAL, STX

Colorado 64 M November Yes

Travel to India and

Korea

Ogawa FUR, STR, SOX, NAL, STX

Florida 71 M November Yes Resident of Haiti Ogawa None

†

*FUR=furazolidone, NAL=nalidixic acid, SOX=sulfisoxazole, STR=streptomycin, STX=trimethoprim-sulfamethoxazole

†

As of late 2015, all V. cholerae isolates sent to CDC undergo antimicrobial susceptibility testing through the National Antimicrobial Resistance Monitoring

System (NARMS) laboratory. The testing scheme and panel of drugs differ from those previously used; therefore, differences in resistance between these

periods should be interpreted with caution

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III. Publications using COVIS data, 2014 and 2015

Loharikar A, Newton AE, Stroika S, Freeman M, Greene KD, Parsons MB, Bopp C, Talkington D, Mintz ED, Mahon

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

Infect. 2015 Mar;143(4):695-703. Available from http://dx.doi.org/10.1017/S0950268814001186

Newton AE, Garrett N, Stroika SG, Halpin JL, Turnsek M, Mody RK. Notes from the field: increase in Vibrio

parahaemolyticus infections associated with consumption of Atlantic Coast shellfish — 2014. MMWR. 2014;63:335–

6. Available from http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6315a6.htm

Martinez-Urtaza J, Baker-Austin C, Jones JL, Newton AE, Gonzalez-Aviles GD, DePaola A. Spread of Pacific

Northwest Vibrio parahaemolyticus strain. N Engl J Med. 2014 Oct 17;369(16):1573–4. Available from

http://www.nejm.org/doi/full/10.1056/NEJMc1305535

Slayton RB, Newton AE, Depaola A, Jones JL, Mahon BE. Clam-associated vibriosis, USA, 1988–2010. Epidemiol

Infections. 2014 May;142(5):1083–8. Available from http://dx.doi.org/10.1017/S0950268813001830

Vugia DJ, Tabnak F, Newton AE, Hernandez M, Griffin PM. Impact of 2003 state regulation on raw oyster–associated

Vibrio vulnificus illnesses and deaths, California, USA. Emerg Infect Dis. 2014 Aug;19(8):1276–80. Available from

http://dx.doi.org/10.3201/eid1908.121861

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Appendix

Method for Classification of Transmission Routes in the Cholera and Other Vibrio Illness

Surveillance (COVIS) System

I. Exposure categories

To classify transmission routes, the first step is to categorize patient exposures. For a given illness episode, >1

patient exposure can be reported to COVIS; each reported exposure is categorized individually. If all exposures

fall into a single category, then the report is considered to have a single exposure category. If not, the report is

considered to have multiple exposure categories. For a given case, if any exposure is reported, we assume that

other exposures for which information was not reported were not present. Exposures are classified using three

categories:

1. Seafood consumption: Ingestion of seafood. Does not include touching seafood.

2. Marine / estuarine contact: Includes direct skin contact with marine / estuarine life, bodies of water, or

drippings from raw or live seafood.

3. Unknown exposure: no exposure history reported.

II. Specimen site categories

The next step in classifying transmission routes is to categorize reported specimen sites. For a given illness

episode, >1 specimen site can be reported; each reported site is categorized individually. If all specimen sites fall

into a single category, then the report is considered to have a single specimen site category. If not, then the report

is considered to have multiple specimen site categories. Specimen sites are classified using five categories:

1. Gastrointestinal site (GI): stool, bile, appendix, rectum, gall bladder, colon

2. Blood or other normally sterile site (sterile): blood, cerebrospinal fluid (CSF), peritoneal fluid, lumbar disc

fluid, lymph node, bullae

3. Skin or soft tissue site (SST): wound, ear (other than otitis media and middle ear, which are included in ‘other,

non-sterile site’), appendage, tissue

4. Other, non-sterile site (ONS): urine, sputum, aspirate, bronchial washing, effusion, catheter, endotracheal, eye,

nasal, placenta, respiratory, sinus, tonsil

5. Unknown site (unknown): no specimen site reported or no site specified for ‘other’

Note: The lists of sites for each category above are not intended to be exhaustive. Rather, they reflect the sites

actually reported to COVIS and can be updated if new sites are reported.

III. Transmission route

The final step in classifying transmission involves review of exposure and specimen site categories for each

reported case. Reports are classified into one of three transmission routes, foodborne, non-foodborne, and

unknown, based on criteria below:

1. Single exposure category: seafood consumption

● Confirmed Foodborne: Vibrio isolated only from GI or sterile site OR Vibrio isolated from multiple specimen

site categories, including a GI site.

● Probable Foodborne: Vibrio isolated only from SST, ONS, or unknown sites OR Vibrio isolated from multiple

specimen site categories, not including GI.

2. Single exposure category: marine / estuarine contact

● Confirmed Non-foodborne: Vibrio isolated only from SST or sterile site OR Vibrio isolated from multiple

specimen site categories, with SST reported.

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NCEZID Atlanta:

For more information please contact Centers for Disease Control and Prevention

1600 Clifton Road NE, Atlanta, GA 30333 MS C-09

Telephone: 1-404-639-2206

Email: cdcinfo@cdc.gov

● Probable Non-foodborne: Vibrio isolated only from GI, ONS, or unknown sites OR Vibrio isolated from

multiple specimen site categories, not including SST.

3. Multiple exposure categories: both seafood consumption AND marine / estuarine contact

● Confirmed Foodborne: Vibrio isolated only from a GI site OR Vibrio isolated from multiple specimen site

categories, with GI reported and SST not reported

● Confirmed Non-foodborne: Vibrio isolated only from a SST site OR Vibrio isolated from multiple specimen

site categories, with SST reported and GI not reported

● Unknown: Vibrio isolated only from a sterile, ONS, or unknown site OR Vibrio isolated from multiple

specimen site categories, including either 1) both GI and SST or 2) neither GI nor SST.

4. Unknown or no reported exposure (note that categorization is the same as for multiple exposure

categories)

● Confirmed Foodborne: Vibrio isolated only from a GI site OR Vibrio isolated from multiple specimen site

categories, with GI reported and SST not reported

● Confirmed Non-foodborne: Vibrio isolated only from a SST site OR Vibrio isolated from multiple specimen

site categories, with SST reported and GI not reported

● Unknown: Vibrio isolated only from a sterile, ONS, or unknown site OR Vibrio isolated from multiple

specimen site categories, including either 1) both GI and SST or 2) neither GI nor SST.