Volume 10, Number 4—April 2004
Research
Ixodid and Argasid Tick Species and West Nile Virus
, Nathalie Yumari Uzcátegui*, Ernest Andrew Gould*, and Patricia Anne Nuttall*
Table 1
Results of immunofluorescence assay (IFA) or nested reverse transcriptase–polymerase chain reaction (RT-PCR) from Ornithodoros moubata and Ixodes ricinus ticks fed on West Nile virus–inoculated BALB/c mice or noninfected mice (co-fed ticks)
| Species | Developmental stage | Days from infection to infestation | Days after engorgementa | IFAb +/– | RT-PCRc (no. positive/no. tested) | |
|---|---|---|---|---|---|---|
| O. moubata |
0 |
1, 2, 7 |
– (8) |
ND |
||
| First bloodmeal
(infected mice) |
Second instar |
1 |
1–7 |
– (5) |
ND |
|
| 2 |
1–7, 14 |
+ (5) |
+ (5) |
|||
| 3 |
1–7, 14 |
+ (5) |
+ (5) |
|||
| 4 |
1, 3, 7 |
– (5) |
ND |
|||
| Third instar |
2 |
22 |
+ (5) |
ND |
||
| 3 |
22 |
+ (5) |
ND |
|||
| 2 |
132 |
+ (5) |
7/14 |
|||
| Second bloodmeal
(uninfected mice) |
Third instar |
2 |
60 (3) |
+ (5) |
+ (5) |
|
| 2 |
64 (7) |
+ (5) |
+ (5) |
|||
| Fourth instar |
2 |
75 (25) |
+ (5) |
+ (5) |
||
| Uninfected co-fed O. moubata ticks |
Second instar |
N/A |
5 |
ND |
15/66 |
|
| Third instar |
N/A |
45 |
ND |
4/15 |
||
| I. ricinus
First bloodmeal (infected mice) |
Nymph |
4 |
2 |
ND |
0/12 |
|
| –3 |
2 |
ND |
2/12 |
|||
| –3 |
30 |
ND |
0/25 |
|||
| BALB/c miced | N/A | N/A | N/A | – (1) | 1/17 | |
aNumber of days after the ticks had completed feeding on inoculated mice when ticks were tested for virus infection. Where given, parentheses depict ticks that had fed a second time and the number of days after which the ticks were tested.
bTick homogenate samples were scored positive if >10% of inoculated C6/36 cells showed specific fluorescence with both 813 and 546 monoclonal antibodies. Numbers of ticks in each pool are shown in parentheses.
cWhere indicated by +, pools of ticks were tested; numbers of ticks in each pool are shown in parentheses. ND, not done.
dMice were infested with infected O. moubata ticks and after 14 days were sacrificed and the brain homogenates tested by IFA and RT-PCR. N/A, not applicable.