Vibrio surveillance in the CIDT Era · 2019-02-19 · Cholera and Other Vibrio Illness Surveillance...

Post on 28-Jun-2020

0 views 0 download

transcript

National Center for Emerging and Zoonotic Infectious Diseases

Vibrio surveillance in the CIDT Era

Erin K. Stokes, MPH

Surveillance Epidemiologist, National Surveillance Team

PulseNet/OutbreakNet West Coast Regional Meeting

February 6, 2019

Cholera and Other Vibrio Illness Surveillance (COVIS)

• National surveillance for vibriosis and cholera • 1988–present (vibriosis nationally notifiable in 2007)

• 144 vibriosis cases in 1988 to over 2,000 in 2017

• Case report form collects information on:• illness and underlying health conditions

• recent seafood consumption

• recent exposure to water or marine life

• source(s) of implicated seafood

• Information from COVIS helps track Vibrio

infections, monitor trends in patient, food, and

environmental risk factors, and to respond to clusters

and outbreaks

2017 Update to Vibriosis Case Definition

CASE CLASSIFICATION • NEW: Supportive laboratory evidence: detection of Vibrio in a clinical specimen by a

culture-independent diagnostic test

• Classified as a probable case

• CONTINUING: Confirmatory laboratory evidence: isolation of Vibrio from a clinical specimen

• Classified as a confirmed case

CRITERION FOR A NEW CASE• NEW: Identification of different species of Vibrio from an individual are

considered separate cases• COVIS will continue collecting data by patient; individuals with multiple species will count as a

single case

Vibriosis Case Classification Based on Culture Results

Culture performed

PositiveConfirmed

case

NegativeNot a case or epi-linked*

*CDC requests that a COVIS form is completed for cases that were epidemiologically linked to a laboratory-identified case

Vibriosis Case Classification Based CIDT Results

CIDT performed

Positive detection of

Vibrio

Reflex culture performed

Positive culture Confirmed Case

Negative Culture Probable Case

No Reflex Culture

PerformedProbable Case

No Vibriodetected

Not a case or epi-linked*

*CDC requests that a COVIS form is completed for cases that were epidemiologically linked to a laboratory-identified case

Surveillance and Response: Culture vs. CIDT

Culture-confirmed CIDT positive

Laboratory results Vibrio species identification (20+ species)

Presence of Vibrio (assays for multiple species or V.

cholerae), test type/name

PFGE

Whole genome sequencing

Antimicrobial susceptibilitytesting

Regulated by the National Shellfish Sanitation Program (NSSP)

V. parahaemolyticus, V. vulnificus

Not included

Vibriosis CIDT Trends, 2017–2018

Trend data are preliminary and subject to change as additional cases or laboratory results are reported

Total vibriosis cases by year reported to COVIS (N=8,605)

0

500

1000

1500

2000

2500

2013 2014 2015 2016 2017 2018

Freq

uen

cy

Year

Cx+ only Cx+/CIDT+ CIDT only Cx-/CIDT+

Confirmed vibriosis cases reported to COVIS, 2017–2018 (N=2,459)

0

200

400

600

800

1000

1200

Freq

uen

cy

Species

Cx+ only Cx+/CIDT+

All vibriosis cases reported to COVIS, 2017–2018 (N=3,635)

0

200

400

600

800

1000

1200

Freq

uen

cy

Species

Cx+ only Cx+/CIDT+ CIDT only Cx-/CIDT+

2017 Vibriosis cases by month (N=2,043)

0

50

100

150

200

250

300

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

Freq

uen

cy

Month

Cx+ only Cx+/CIDT+ CIDT only Cx-/CIDT+

2018* Vibrio cases by month (N=1,581)

*2018 data has not been received from all reporting partners

0

20

40

60

80

100

120

140

160

180

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

Freq

uen

cy

Month

Cx+ only Cx+/CIDT+ CIDT only Cx-/CIDT+

Case Classification by Region, 2017–2018 (N=3,635)

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Atlantic Gulf Coast Noncoastal Pacific

Reporting Region

Cx+ only Cx+/CIDT+ CIDT only Cx-/CIDT+

Characteristics of vibriosis cases identified from a stool specimen, 2017–2018

Trend data are preliminary and subject to change as additional cases or laboratory results are reported

Probable (N=1,176) vs. Confirmed (N=1,353): Foodborne Exposures, 2017–2018

19%

47%

60%

80%

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

Ate oysters or clams

Ate any seafood

Confirmed Probable

PROBABLE

Confirmed cases report higher rates of:• Consumption of oysters or

clams• Overall seafood

consumption

Probable (N=1,176) vs. Confirmed (N=1,353): Water Exposures, 2017–2018

Confirmed cases report higher rates of:• Exposure to a body of

water• Any marine exposure

(water, marine life, or drippings from seafood)16%

12%

30%

20%

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

Any marine exposure

Exposure to abody of water

Confirmed Probable

Probable (N=1,176) vs. Confirmed (N=1,353): Clinical Compatibility, 2017–2018

Probable and confirmedcases have similar rates of:

• diarrhea

• visible blood in stools

• vomiting

• cramps

86%

15%

33%

60%

90%

12%

34%

65%

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Diarrhea Visible Blood in Stool Vomiting Cramps

Probable Confirmed

Probable (N=1,176) vs. Confirmed (N=1,353): Co-detection, 2017–2018

8% of confirmed cases and 18% of probablecases report detection of one or more non-Vibrio organisms

(There had to be a meme somewhere in here)

To Summarize…

• Reporting of probable CIDT positive cases to COVIS began in 2017

• Total cases reported increased considerably in 2017 as well as culture confirmed cases, and a large portion were probable cases without an identified species

• Consumption of seafood, especially shellfish, is lower in probable cases

• Exposure to water as well as other marine exposures is lower in probable cases

• Confirmed and probable cases have similar reporting of GI symptoms

• Co-detections are higher in probable cases

So…

Are a portion of CIDT detected cases “false positives”?

Potential considerations to answer this question…• Do all true positives have a seafood or water exposure?

• How should cases lost to follow-up be treated?

• What factors are associated with the varying detection rates in different regions?

• Logistical reasons that lead to detection but no growth on cultures?

• Are we getting the full story in COVIS?

• If there are false positives, how would they be defined?

Complete reporting is needed to evaluate differences between confirmed and probable cases

• CIDT detected cases, regardless of culture result meet the current national vibriosis case definition

• COVIS team will continue working with FoodNet, APHL, and state partners to analyze CIDT results and update guidance for reporting if appropriate

• If resources are limited, prioritize investigations for culture confirmed cases

For more information, contact CDC1-800-CDC-INFO (232-4636)TTY: 1-888-232-6348 www.cdc.gov

The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention.

Questions? Email: COVISResponse@cdc.gov

Thank you to:National Surveillance Team

State PartnersFoodNet