Sampling considerations for a potential Zika virus urosurvey in New York City

• Published in: Epidemiology and infection Vol. 146; no. 13; pp. 1628 - 1634
• Main Authors: Thompson, C. N., Lee, C. T., Immerwahr, S., Resnick, S., Culp, G., Greene, S. K.
• Format: Journal Article
• Language: English
• Published: Cambridge, UK Cambridge University Press 01.10.2018
• Subjects: Approximation; Aquatic insects; Arboviruses; Archives & records; Binomial distribution; Censuses; Confidence intervals; Contingency; Contingency planning; Contingency plans; Diagnostic Tests, Routine - methods; Disease transmission; Emergency preparedness; Households; Humans; Hygiene; Infections; Information systems; Information technology; Mosquitoes; New York City - epidemiology; Original Paper; Population density; Population statistics; Population Surveillance - methods; Postal & delivery services; Prevalence; Sampling Studies; Sensitivity and Specificity; Software; Urban environments; Urine; Urine - virology; Vector-borne diseases; Veterinary medicine; Viruses; Zika virus; Zika Virus - isolation & purification; Zika Virus Infection - epidemiology; New York City; New York; Florida; United States > US; Texas; Utah; urosurvey; Zika virus; Local transmission; sampling
• ISSN: 0950-2688; 1469-4409; 1469-4409
• DOI: 10.1017/S0950268818002236

In 2016, imported Zika virus (ZIKV) infections and the presence of a potentially competent mosquito vector (Aedes albopictus) implied that ZIKV transmission in New York City (NYC) was possible. The NYC Department of Health and Mental Hygiene developed contingency plans for a urosurvey to rule out ongoing local transmission as quickly as possible if a locally acquired case of confirmed ZIKV infection was suspected. We identified tools to (1) rapidly estimate the population living in any given 150-m radius (i.e. within the typical flight distance of an Aedes mosquito) and (2) calculate the sample size needed to test and rule out the further local transmission. As we expected near-zero ZIKV prevalence, methods relying on the normal approximation to the binomial distribution were inappropriate. Instead, we assumed a hypergeometric distribution, 10 missed cases at maximum, a urine assay sensitivity of 92.6% and 100% specificity. Three suspected example risk areas were evaluated with estimated population sizes of 479–4,453, corresponding to a minimum of 133–1244 urine samples. This planning exercise improved our capacity for ruling out local transmission of an emerging infection in a dense, urban environment where all residents in a suspected risk area cannot be feasibly sampled.