A Brilliant Study on the Frequency of Antibodies
Against Tick Saliva Shows Frequent
Tick Bites in California
When your body senses an invading infection it makes antibodies to attack the infection. The part of the infection invading is called an "antigen" but it is simply some protein or other part of the invading infection. In this stunning study below, Dr. Lane showed that in parts of California, people have been bitten by special common ticks that carry Lyme disease as often as 36%, e.g., the tick I. pacificus among residents of the San Francisco Bay region. He found antibodies in the blood of California residents against the tick's specific saliva. This shows they had to have been bitten to get saliva into the person's blood.
Anti-arthropod saliva antibodies among residents of a community at high risk for Lyme disease in California.
Department of Environmental Science, Policy and Management, University of California, Berkeley 94720, USA.
The role of the western black-legged tick (Ixodes pacificus) versus that of other potential arthropod vectors in the epidemiology of Lyme disease was evaluated by determining the prevalence of anti-arthropod saliva antibodies (AASA) among residents (n = 104) of a community at high-risk (CHR).
Salivary gland extracts [were] prepared from:
- I. Pacificus [a common Lyme carrying tick]
- the Pacific Coast tick (Dermacentor occidentalis)
- the western cone-nose bug (Triatoma protracta)
- the western tree-hole mosquito (Aedes sierrensis)
[All four] were used as antigens in an ELISA.
Sera from 50 residents of the San Francisco Bay region in northern California and 51 residents of Imperial County in southern California served as comparison groups.
The prevalence of AASA ranged from 2% for A. sierrensis to 79% for I. pacificus in study subjects, 0% for D. occidentalis to 36% for I. pacificus among residents of the San Francisco Bay region, and 6% for I. pacificus to 24% for A. sierrensis in residents of Imperial County.
The associations between AASA and demographic factors, potential risk factors, probable Lyme disease, and seropositivity for Borrelia burgdorferi were assessed for 85 members of the CHR. Seropositivity for I. pacificus and B. burgdorferi were significantly correlated, the relative risk of seropositivity to B. burgdorferi was about 5 (31% versus 6%) for subjects who were seroreactive to I. pacificus, nearly every individual who was seropositive for B. burgdorferi had elevated levels of antibodies to I. pacificus, and the mean titer for antibodies to I. pacificus was significantly higher for subjects seropositive versus those seronegative for B. burgdorferi. Together, these findings support the widely held belief that I. pacificus is the primary vector of B. burgdorferi for humans in northern California, and they demonstrate the utility of the AASA method as an epidemiologic tool for studying emerging tick-borne infections.
Lane RS, Moss RB, Hsu YP, Wei T, Mesirow ML, Kuo MM. American Journal of Tropical Medical and Hygiene. 1999;61:850-9.
PMID: 10586924 [PubMed - indexed for MEDLINE]
[Inserts, spacing, adjusted formatting, list creation, bolding and underlines by Dr. Schaller]
Dr. Schaller would like to thank this creative and brilliant scientist and scholar for this important research.