Transmission potential of African, Asian and American Zika virus strains by Aedes aegypti and Culex quinquefasciatus from Guadeloupe (French West Indies)

Figures & data

Table 1. Characteristics of the virus strains used in this study.

Zika virus strain^a	Origin	Year of first isolation	Viral stock passage history^b	% nucleotide relatedness			GenBank Accession number
				Senegal	Martinique	Malaysia
Senegal	African	1984	P5	–	–	–	KU955592
Martinique	American	2015	P4	88,91	–	–	KU647676
Malaysia	Asian	1966	P5	90,35	95,56	–	KX694533

^aSupplier strain names: Senegal: Dak84; Martinique: MRS_OPI_Martinique_PaRi_2015; Malaysia: MAS66.

^bVero cells (ATCC, Ref.CCL – 81) were used for all the virus passages.

Table 2. Infection rates, dissemination rates, and transmission rates of Culex quinquefasciatus and Aedes aegypti mosquitoes from Guadeloupe at 7, 14 and 21 days post-infection, calculated for three different ZIKV strains. Blood meal titer was 10⁷ TCID₅₀/ml for all the experiments. Values in bold correspond to rates significantly different between ZIKV strains, mosquito species and days post-infection (Fisher's exact test, P < 0.0001).

Mosquito species	ZIKV strains	Infection rate (%)			Dissemination rate (%)			Transmission rate (%)
		Day post infection			Day post infection			Day post infection
		7	14	21	7	14	21	7	14	21
Culex quinquefasciatus	Senegal (African)	0	0	0	0	0	0	0	0	0
		(30)	(30)	(28)	(30)	(30)	(28)	(30)	(30)	(28)
	Malaysia (Asian)	0	0	0	0	0	0	0	0	0
		(13)	(25)	(23)	(13)	(25)	(23)	(13)	(25)	(23)
	Martinique (American)	0	0	0	0	0	0	0	0	0
		(20)	(18)	(26)	(20)	(18)	(26)	(20)	(18)	(26)
Aedes aegypti	Senegal (African)	90	92	84.6	96.3	91.3	95.5	42.3	61.9	76.2
		(30)	(25)	(26)	(30)	(25)	(26)	(30)	(25)	(26)
	Malaysia (Asian)	23.3	23.3	16.7	28.6	71.4	80	0	20	75
		(30)	(30)	(30)	(30)	(30)	(30)	(30)	(30)	(30)
	Martinique (American)	23.3	36.7	26.7	28.6	54.5	62.5	0	0	80
		(30)	(30)	(30)	(30)	(30)	(30)	(30)	(30)	(30)

Note: Numbers in parentheses correspond to the number of analysed mosquitoes.

Figure 1. Infection rate (± CI) (a), dissemination efficiency (± CI) (b), and transmission efficiency (± CI) (c) of Aedes aegypti from Guadeloupe fed with ZIKV at 7, 14 and 21 days post-infection (dpi). For each modality, a batch of 30 mosquitoes was analysed except for African ZIKV at 14 dpi (N = 25) and 21 dpi (N = 26). Asterisks indicate significant differences between the estimated parameters according to ZIKV strains and dpi (Fisher's exact test; ***: P < 0.0001). ND: Not Detected.

Figure 2. Viral loads in saliva of Ae. aegypti infected with ZIKV Senegal, ZIKV Martinique or ZIKV Malaysia at 7, 14 and 21 days post-infection. Dots, triangles and rhombuses, represent the titer of each infected saliva. Horizontal grey bars represent means (± SE).