Imported arboviral infections in New Zealand, 2001 to 2017: A risk factor for local transmission

Abstract

Background/aimsOver the last decade and following international trends, cases of mosquito-borne arboviral infections, notably dengue fever, chikungunya and Zika, have increased among travellers arriving in New Zealand, but no locally acquired cases have been identified. Imported cases are characterised and examined to identify trends and features that might assist in reducing transmission risk from travellers. MethodsInformation on traveller arrivals, notified cases and risk factors for disease acquisition were obtained from national sources. Trends in importation rates, seasonality are described and relationships of notifications with traveller arrivals were examined with a negative binomial regression model. ResultsThere was a significant increase in dengue notifications combined with the emergence of Zika and chikungunya. Most notifications were from arrivals in Auckland from Pacific Islands during summer and early autumn. Conclusion/implicationsOverseas travel from New Zealand, particularly to the Pacific Islands and Southeast Asia, involves a risk of arboviral infection. The repeated introduction of arboviruses to New Zealand also increases the risk of local transmission in a country that has vector capable and vector potential mosquitoes, as well as an increasingly suitable climate for new vectors to establish.