TY - JOUR
T1 - Acquisition and transmission of Theileria parva by vector tick, Rhipicephalus appendiculatus
AU - Konnai, Satoru
AU - Imamura, Saiki
AU - Nakajima, Chie
AU - Witola, William Harold
AU - Yamada, Shinji
AU - Simuunza, Martin
AU - Nambota, Andrew
AU - Yasuda, Jun
AU - Ohashi, Kazuhiko
AU - Onuma, Misao
N1 - Funding Information:
The encyclopedic T. parva detection knowledge of Dr. Richard Bishop, International Livestock Research Institute, and Dr. Vishvanath Nene, The International Institute for Genomic Research, are gratefully appreciated. We wish to thank Mr. Chota Amos and Mr. Mwelwa Chembensofu, for technical assistance. This research was sponsored by Grants-in-Aid for Scientific Research from the Japan Society the Promotion of Science.
PY - 2006/8
Y1 - 2006/8
N2 - In order to investigate the transmission dynamics of Theileria parva (T. parva) by the brown ear tick, Rhipicephalus appendiculatus (R. appendiculatus), under experimental conditions, detection of T. parva in ticks and cattle was performed by a quantitative real-time PCR assay. A calf inoculated with a T. parva mixture became PCR-positive for T. parva infection on day 8 post-inoculation, and subsequently, nymphal ticks were introduced and maintained to feed on the infected calf for 6 days. Engorged nymphs were collected daily and allowed to molt into adults, and overall, 70.8% (121/171) of the adult ticks acquired the T. parva infection. Furthermore, the T. parva infection rate in ticks under field conditions was monitored by real-time PCR in R. appendiculatus ticks collected from a traditionally managed pastoral land of Zambia, on which Sanga breed cattle are traditionally reared and the area has endemic East Coast fever (ECF). A total of 70 cattle were randomly selected in the same area and 67 (95.7%) were found to be serologically positive for R. appendiculatus tick antigen (RIM36). Twenty-nine (43.3%) of the 67 serologically positive cattle were real-time PCR-positive for T. parva, although no piroplasms could be detected in the blood smears. Unexpectedly, out of 614 R. appendiculatus nymphal and adult ticks collected by flagging vegetation, 4.1% were positive for T. parva DNA. However, since the rate of transmission of T. parva from infected cattle to ticks and vice versa and the serological evidence of exposure to R. appendiculatus ticks in naturally exposed cattle were relatively high, it would be wise in such a case to consider vector control as well as vaccination against ECF as control measures.
AB - In order to investigate the transmission dynamics of Theileria parva (T. parva) by the brown ear tick, Rhipicephalus appendiculatus (R. appendiculatus), under experimental conditions, detection of T. parva in ticks and cattle was performed by a quantitative real-time PCR assay. A calf inoculated with a T. parva mixture became PCR-positive for T. parva infection on day 8 post-inoculation, and subsequently, nymphal ticks were introduced and maintained to feed on the infected calf for 6 days. Engorged nymphs were collected daily and allowed to molt into adults, and overall, 70.8% (121/171) of the adult ticks acquired the T. parva infection. Furthermore, the T. parva infection rate in ticks under field conditions was monitored by real-time PCR in R. appendiculatus ticks collected from a traditionally managed pastoral land of Zambia, on which Sanga breed cattle are traditionally reared and the area has endemic East Coast fever (ECF). A total of 70 cattle were randomly selected in the same area and 67 (95.7%) were found to be serologically positive for R. appendiculatus tick antigen (RIM36). Twenty-nine (43.3%) of the 67 serologically positive cattle were real-time PCR-positive for T. parva, although no piroplasms could be detected in the blood smears. Unexpectedly, out of 614 R. appendiculatus nymphal and adult ticks collected by flagging vegetation, 4.1% were positive for T. parva DNA. However, since the rate of transmission of T. parva from infected cattle to ticks and vice versa and the serological evidence of exposure to R. appendiculatus ticks in naturally exposed cattle were relatively high, it would be wise in such a case to consider vector control as well as vaccination against ECF as control measures.
KW - Detection
KW - Monitoring
KW - Real-time PCR
KW - Theileria parva
KW - Transmission
UR - http://www.scopus.com/inward/record.url?scp=33748749174&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33748749174&partnerID=8YFLogxK
U2 - 10.1016/j.actatropica.2006.06.008
DO - 10.1016/j.actatropica.2006.06.008
M3 - Article
C2 - 16899209
AN - SCOPUS:33748749174
SN - 0001-706X
VL - 99
SP - 34
EP - 41
JO - Acta Tropica
JF - Acta Tropica
IS - 1
ER -