Epidemiologic investigation of a family cluster of imported ZIKV cases in Guangdong, China: probable human-to-human transmission

Abstract

Zika virus (ZIKV) is an emerging mosquito-borne flavivirus that can potentially threaten South China. A Chinese family of four returning from Venezuela to China was found to be positive for ZIKV when the youngest son's fever was first detected at an airport immigration inspection. They were isolated temporarily in a local hospital in Enping city, Guangdong province, where their clinical data were recorded and urine and saliva were collected to isolate ZIKV and to obtain viral sequences. All of them except the mother presented mild symptoms of rash and fever. Envelope gene sequences from the father, daughter and son were completely identical. Phylogenetic analysis demonstrated that this strain is similar to several imported strains reported in recent months, which are all clustered into a group isolated from 2015 ZIKA outbreaks in Brazil. Together with the climatic features in Venezuela, New York and Guangdong in February, it can be concluded that our subjects are imported cases from Venezuela. With the same viral sequence being shared between family members, neither direct human-to-human nor vector transmission can be ruled out in this study, but the former seems more likely. Although our subjects had mild illness, epidemiologists and public health officials should be aware of the risk of further expansion of ZIKV transmission by local competent vectors.

Intranasal infection and contact transmission of Zika virus in guinea pigs

“…Finally, it remains unknown whether similar direct contact transmission modes observed in guinea pigs have occurred in human populations, and the contribution of contact transmission route during the explosive ZIKV pandemic remains elusive 40 . Very recently, infectious DENV have been recovered directly from respiratory specimens from patients with cough, rhinorrhea, and nasal congestion 41 .…”

Zika virus: History, epidemiology, transmission, and clinical presentation

“…2, ZIKV is a potential pandemic threat, currently circulating not only in the Americas but also in the Pacific Islands (American Samoa, Federated States of Micronesia, Fiji, Marshall Islands, New Caledonia, Palau, Papua New Guinea, Samoa, and Tonga), Southeast Asia (Singapore, Thailand, the Philippines, and Vietnam), and the islands of Cape Verde off the coast of West Africa (CDC, 2016a; ECDC, 2016a; WHO, 2016b). In addition, since early 2015, there have been an increasing number of travel-related imported ZIKV cases in non-endemic countries: Australia (AGDH, 2016;Pyke et al, 2016), Belgium (De Smet et al, 2016), Canada (GC, 2016), China (Yin et al, 2016;Zhang et al, 2016b), France (Maria et al, 2016), the US (Hawaii) (CDC, 2016b), Italy (Nicastri et al, 2016b), Portugal (Ze-Ze et al, 2016), Spain (Diaz-Menendez et al, 2016), Switzerland (Gyurech et al, 2016), and the Netherlands (Duijster et al, 2016). Using species distribution modeling techniques, a recent study has predicted that a large portion of the tropical and sub-tropical regions of the globe has suitable environmental conditions but has not yet reported symptomatic cases of ZIKV infection (Fig.…”

Suggested mechanisms for Zika virus causing microcephaly: what do the genomes tell us?

“…Not only the clinical manifestations of the virus have changed, its mode of transmission also seems to be changing, as cases caused by sexual transmission are increasing [ 11 ], and the first cases of human-to-human transmission have now been described [ 12 , 13 ]. It appears that during the past decade the infectivity of ZIKV increased, resulting in larger outbreaks, and symptoms got more severe, but no evidence of microcephaly has been observed until the virus hit Brazil.…”