1989 Military Study- Ticks and Diseases

This is a well-documented 1989 Military Report (guidelines for physicians, etc.) that might possibly be useful for patients in the military (and others) if they need background information, especially to comply with “red tape” requirements.

Some quotes I found interesting (posted below). Copying and pasting from the original document accounts for the odd font patterns. Link to entire article is at the bottom of the page.

Lucy Barnes

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140 page document



SEPTEMBER 1989 '' Approved for public release; distribution is unlimited.


Medical Entomology Section, Epidemiology Division, USAF

School of Aerospace Medicine, Human Systems Division (AFSC) Brooks Air Force Base, Texas 78235-5301

This special report contains a worldwide overview of the tick species and tick borne diseases potentially affecting military operations. Chapters on history of tick borne dis- ease, biology/ecology of ticks, major tickborne diseases, species discussions, and manage- ment of tick problems during deployments are included. Photographs and/or drawings are provided for the medically important species occurring worldwide. This report serves as a guide for physicians, 'environmental health, veterinary, and pest management personnel.

Quotes Below...

Needless to say, in an area infested with ticks to the degree that Camp Bullis was in the 1940s (regardless of the disease transmission potential), troops are not going to be able to execute their military duties at an optimal level.

There is probably some tolerance threshold (see Chapter 3) beyond which duty performance is significantly affected and thus drastic iick control measures are warran;ted, and the author thinKs everyone would agree that 1,150 ticks on one soldier is above that tolerance threshold.

In 6 of the 9 classes, approximately 40% or more students received >10 ticks during training. Class 88-10 (May 30-June 12) had 65% of respondents reporting at least 10 tick bites. Ten people, mostly in the first 4 classes, reported >100 ticks attached to them during the 2-week training period.

Approximately one-third of each class reported that ticks had a significant impact on the performance of their military duties. Of those students receiving >50 ticks during training, 66% (21/32) felt that ticks had a significant impact on their duty performance.

The use of nonchemical, mostly folklore, tick-repellent methods was occasionally noted on questionnaires. These methods included pantyhose, flea/tick collars, Avon Skin-so-Soft, vitamin C, and double-sided tape.

If the impact of tick bites is largely emotional distress, even a modicum of information may reduce troop aversion to ticks, reduce the psychological impact of attachment, and allow troops to concentrate on military duties.

Adult ticks are more adept at traveling through vegetation than the minute larvae. Studies have shown that adult lone star ticks may travel up to 10 m (33 ft) to a C02 source, but other species such as Ixodes dammini will only travel distances of 1-2 m (3.3 - 6.6 ft) toward a C02 source.

(pg. 16) There are different types of sex pheromones, but probably the best known example is the attractant sex pheromone, 2,6-dichlorophenol (2,6-DCP) which has been shown to be attractive to numerous ixodid tick species. The compound serves as an excitant, inducing males to detach, as well as a locating signal of the emitting source, thus guiding the male to the sexually active female.

Development, activity, and survival of hard ticks is influenced greatly by temperature and humidity within the tick's micro-habitat. Lancaster (1957) found that lone star tick eggs reared in an environment of <75% humidity would not hatch. Lees (1946) showed that Ixodes ricinus died within 24 h if kept in a container of 0% relative humidity (RH), but survived 2-3 months at 90% RH. The tick Hyalomma savignvi survived almost 7 months at 17.5 OC (63.5 F) but less than 3 weeks at 370C (98.6 0F) (Feldman-Muhsam 1947).

For an example of personal protection, Schreck et al. (1986) demonstrated in a research study that military field uniforms treated with 0.5% permethrin provided 100% protection to humans against all life stages of Ixodes dammini.

Vegetation management may reduce tick numbers. Some legumes produce viscous secretions from glandular trichomes on the stems which trap and kill larval ticks as they attempt to quest for hosts. However, Norval et al. (1983) in Zimbabwe showed that legumes in the genus Stylosanthes were repellent to ticks with larval ticks selectively avoiding them.

Camp site and/or training site selection is important in avoiding tick-infested areas. Knowing what we know about tick habitat preferences (Chapter 2), troops on maneuvers should avoid ecotonal areas such as forest boundaries surrounding old fields or other clearings.

For an aerial dispersal of acaricide, an aerial spray validation statement is required as well as an environmental assessment and proper coordination with local, state, and sometimes federal officials. Roberts et al. (1980) and Mount (1981) confirmed the efficacy of diazinon granules for control of lone star ticks. Mount (1984) used 14% diazinon granules at 7 lb/acre in an aerial spray treatment fcr tick control in Oklahoma and attained 97% control of lone star nymphs and 82% control of adults.

In contrast, the Army used diazinon 14G granules for tick control at Ft A.P. Hill, Virginia with less desirable results (Sardelis et al. 1989). A helicopter- transported granular spreader calibrated at 4 lb of granules/acre was used to treat a 700-acre site near Richmond, Virginia.

Wide masking tape placed around the ankles or thighs, leaving the sticky side exposed, works quite well against ticks crawling up the legs.

Many unorthodox (or questionable, at least) methods of tick protection are commonly used by military personnel. Flea collars worn around the ankles, Avon Skin-so-Soft, vitamin C, garlic, sulfur powder, panty hose, and others have been reported to me as "great tick repellents."

The disease was named after the Connecticut community of Old Lyme, where outbreaks of arthritis in 1974 and 1975 were diagnosed as juvenile rheumatoid arthritis. Two persistent housewives living in Lyme questioned this diagnosis and the rheumatology department of Yale University Medical School conducted detailed clinical and epidemiologic investigations that eventually led to the description of a new disease entity called Lyme arthritis or Lyme disease (Steere et al. 1977).

Several ether species, such as Amblyomma americanum and Dermacentor variabilis, have been found to be infected with LD spirochetes (Schulze et al. 1984; Anderson et al. 1985), but their vector potential is probably slight (Piesman and Sinsky, 1988). The agent has also been recovered from horse flies and mosquitoes, thus indicating that transmission by other blood-feeding arthropods may be possible.

When infected ticks feed, rickettsiae are transmitted to the host via salivary secretions.

Although RMSF occurs year-round, most cases occur from April through September when environmental conditions are optimal for tick activity. Persons at greatest risk are the very young, the old, and blacks.

Boutonneuse fever (BF) is a rickettsial disease resembling a mild form of RMSF and is characterized by mild to moderately severe fever, a rash usually involving the palms and soles, and a black button-like lesion (eschar) at the site of tick bite. The fatality rate is < 3%, even without treatment.

Pajaroella Tick- Medical Importance: Although not positively linked to disease transmission, this species produces a "venomous bite" that is reported to be very painful (Failing et al. 1972). There are many tales about the seriousness of the bite, and the tick is said to be feared like a rattlesnake by certain native Mexicans. This species (Figs. 12, 13) occurs along the Pacific Coast of California into Oaxaca and Chiapas States, Mexico. However, collections have recently been made in extreme southern Oregon (Keirans, 1987).

Ornithodoros moubata is often found in cracks in walls and in the earthen floors of huts. An 0. moubata female usually lays 6 or 7 batches of eggs (several hundred per batch) during her lifetime. Larvae do not feed; nymphs engorge in about 20-25 min. There are usually 4nymphal molts for males and 5 for the females. This species is able to live up to 5 years without feeding (Walton, 1960).

Amblyomma americanum is probably the most annoying and commonly encountered tick occurring in the southern U.S. In some rural areas almost every person has been bitten by these ticks at one time or another…. Females usually deposit 3,000-8,000 eggs.

The female lone star tick is often falsely referred to as the "spotted fever tick" because of the single white spot visible on its back. However, this spot has nothing to do with the presence or absence of RMSF organisms. Amblyomma americanum adults have very long mouthparts and can produce painful bites.

(pg. 76) Larval A. hebraeum, like their U.S. cousins, lone star ticks, are troublesome pests of people. They attach themselves in large numbers on the legs and about the waist causing intense irritation, rash-like lesions, and occasionally pustules. Unfed larvae may live for up to 11 months, nymphs for 8 months or more, and adults 22 months or longer. Females deposit about 15,000 eggs.

Yellow Dog Tick- In addition, human infection with the rickettsia may also be acquired by contamination of the skin and eyes with infectious tick fluids from crushing this species while deticking dogs. … Unfed larvae may survive at least 169 days, nymphs 52 days, and adults 210 days (Hoogstraal, 1956). Females lay up to 5,000 eggs.

(pg 106) Ixodes dammini transmits the causative agent of Lyme disease in the New England and midwestern areas of the U.S. and has also been incriminated as a vector of the protozoan, Babesia microti, on Nantucket Island, Massachusetts.

(pg. 107) This species (Figs. 54, 55) occurs in the New England states and New York, south into New Jersey, Virginia, and Maryland; there are also established populations of I. damni in Wisconsin and Minnesota as well as Ontario, Canada. There have been recent reports (1987-88) of j. dammini from Michigan, Iowa, Illinois, and Indiana; Spielman et al. (1985) proposed that the species is extending its range.

Infection rates of I. pacificus with Lyme disease spirochetes are usually in the range of 1-5% compared to rates of 25-75% in I. dammini. This effect may be related to host preferences of the immatures. Ixodes pacificus imma- tures feed predominantly on the western fence lizard (which is refractory to Borrelia burqdorfer iinfection).

I. scapularis inflicts a painful bite.

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