Are Pending Zika Samples Antibody Positive Cases?

[niman]

Tonight's Florida DoH update included four cases in Wynwood which were antibody confirmed.  These were symptomatic cases from July and may have initially tested negative on the urine PCR test because samples were collected late.  Since the cases had been symptomatic and were linked to Zika positive cases, serum was tested for Zika antibodies, which then were confirmed by the CDC, after testing for antibody activity against Dengue and Chikungunya. 

These four cases had been listed as "pending" in the Wynwood investigation table since August 12, raising the possibility that samples that are pending for an extended period are samples that are antibody positive for Zika (as determined by Florida DoH) but have not yet been tested by the CDC for levels against Dengue or Chikungunya.  Since these samples are from cases linked to a Zika confirmed index case for each investigation, samples that are antibody positive for Zika are likely to remain Zika positives after CDC testing.

Several of the Miami Dade investigation have samples that have been "pending" since August 17, raising concerns that these investigation will be designated as active transmission clusters when the CDC does the confirmatory testing,

Edited August 24, 2016 by niman

[niman]

Discussion of the above

 

[niman]

The four individuals in Miami-Dade were identified within the Wynwood area and experienced symptoms of Zika in mid-July. However, the cases are being announced today following confirmatory antibody testing to rule out other mosquito-borne illness such as Dengue and Chikungunya.

http://www.floridahealth.gov/newsroom/2016/08/082316-zika-update.html

[niman]

Updated tables on active investigation cases

Wyn	8-Aug	437	418	11	8
	9-Aug	455	424	17	14
	10-Aug	498	424	16	46
	11-Aug	511	480	19	12
	12-Aug	517	492	21	4
	15-Aug	518	492	22	4
	16-Aug	518	492	22	4
	17-Aug	518	492	23	4
	18-Aug	519	492	23	4
	19-Aug	519	492	23	4
	22-Aug	519	492	23	4
	23-Aug	519	492	29	0
MD2	5-Aug	11
	8-Aug	19	16	0	3
	9-Aug	19	16	0	3
	10-Aug	19	18	0	1
	11-Aug	19	18	0	1
	12-Aug	19	19	0	0
	15-Aug	21	19	0	2
	16-Aug	21	19	0	2
	17-Aug	21	19	0	2
	18-Aug	21	19	0	2
	19-Aug	21	19	0	2
	22-Aug	21	19	0	2
	23-Aug	21	19	0	2
PB	8-Aug	1	0	0	1
	9-Aug	1	0	0	1
	10-Aug	3	0	0	3
	11-Aug	3	2	0	1
	12-Aug	3	3	0	0
	15-Aug	3	3	0	0
	16-Aug	3	3	0	0
	17-Aug	3	3	0	0
	18-Aug	3	3	0	0
	19-Aug	3	3	0	0
	22-Aug	3	3	0	0
	23-Aug	3	3	0	0
MD3	17-Aug
	18-Aug
	19-Aug
	22-Aug
	23-Aug
MD4	15-Aug	5	1	0	4
	16-Aug	5	1	0	4
	17-Aug	6	1	0	5
	18-Aug	6	1	0	5
	19-Aug	6	1	0	5
	22-Aug	6	1	0	5
	23-Aug	6	1	0	5
MD5	17-Aug	2	0	0	2
	18-Aug	2	0	0	2
	19-Aug	2	0	0	2
	22-Aug	8	6	0	2
	23-Aug	26	6	0	20
MD6	17-Aug
	18-Aug
	19-Aug
	22-Aug	comb
	23-Aug
MD7	18-Aug
	19-Aug
	22-Aug
	23-Aug
MD8	18-Aug
	19-Aug
MB	22-Aug	comb		5
MD9	19-Aug
	22-Aug	comb
PIN	23-Aug	3	0	0	3

 

Edited August 24, 2016 by niman

[niman]

• Pregnant women and their sexual partners who are concerned about potential Zika virus exposure may also consider postponing nonessential travel to all parts of Miami-Dade County.

https://www.cdc.gov/media/releases/2016/p0819-zika-miami-beach.html

[niman]

And investigations into local cases can take days to weeks.  It is not quick or easy to determine if cases are locally acquired and if they're related.  Because of this, there may be a time lag between the spread of disease locally and the recognition of that spread.  That is one reason we would advise everyone living in or traveling to Miami-Dade County to be aware that Zika could be spreading there and to enhance their efforts to avoid mosquito bites.  And as indicated previously, pregnant women and their sexual partners who are concerned about Zika infection might consider postponing nonessential travel to Miami-Dade County. 

http://www.cdc.gov/media/releases/2016/t0819-zika-update.html

[niman]

Note astrisk on pending column

ACTIVE INVESTIGATIONS

The department is currently conducting 10 active investigations.

1)    Identified one-square mile in Miami-Dade – Two (2) original cases

Total # of Samples Collected	Negative Samples	Positive Samples	Pending Results
519	492	27	0

Door to door outreach and sampling continue. Mosquito abatement and reduction activities are on-going.

The department has cleared three portions within the one-square mile as no additional people tested positive in those areas. The CDC continues to monitor the area per their guidelines.

2)    First Miami-Dade investigation outside of Wynwood: One (1) case

Total # of Samples Collected	Negative Samples	Positive Samples	Pending Results*
21	21	0	0

 *Awaiting confirmatory testing from CDC to rule out infection.

3)    One (1) case in Palm Beach County:

Total # of Samples Collected	Negative Samples	Positive Samples	Pending Results
3	3	0	0

4) Second Miami-Dade investigation outside of Wynwood: One (1) case

The investigation is beginning in this area in Miami-Dade County. Mosquito abatement and reduction activities will take place around the area of interest.

 5) Third Miami-Dade investigation outside of Wynwood: One (1) case

Total # of Samples Collected	Negative Samples	Positive Samples	Pending Results
6	1	0	5

 
6) Fourth Miami-Dade investigation outside of Wynwood: One (1) case

Total # of Samples Collected	Negative Samples	Positive Samples	Pending Results
27	24	0	3

7) Sixth Miami-Dade investigation outside of Wynwood: One (1) case

The investigation is beginning in this area in Miami-Dade County. Mosquito abatement and reduction activities will take place around the area of interest

8) Miami-Beach Investigation: Five index cases, 3 are out of state

The investigation is beginning in this area in Miami-Dade County. Mosquito abatement and reduction activities will take place around the area of interest

Total # of Samples Collected	Negative Samples	Positive Samples	Pending Results
97	0	0	97

9) Pinellas Investigation: One (1) case

Total # of Samples Collected	Negative Samples	Positive Samples	Pending Results
3	0	0	3

 

10) Second Palm Beach County Investigation: One (1) case

The investigation is beginning in Palm Beach County. Mosquito abatement and reduction activities will take place around the area of interest.

 

CLOSED INVESTIGATIONS

• The department has closed out the investigations into the first cases in Miami-Dade and Broward County (two cases). On Aug. 23, the department had enough information to close two of the ongoing investigations in Miami-Dade County, both were determined to be single cases with no additional transmission or linkage to areas of active transmission. 

 

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_{Data as of Aug. 25, 2016 - 6:15pm EST}

Edited August 26, 2016 by niman