Bulletin 1150 September 2006 Mississippi Agricultural & Forestry Experiment Station Vance H. Watson, Director Robert H. Foglesong, President • Mississippi State University • Vance H. Watson, Vice President A Guide to the Ticks of Mississippi MississiJpeprioDmeepaGrtomdednatrod f Health Department of EnBtolamkoeloLgayytaonn d Plant Pathology Mississippi State University The authors gratefully acknowledge Dr. J.E. Keirans and Dr. L.A. Durden at the Institute for Arctkhnroopwoldeodloggmyeanntsd:Parasitology at Georgia Southern University for identifying unfamiliar specimens and provid - ing the National Tick Collection (Rocky Mountain Laboratory) records of Mississippi ticks. In addition, Dr. Durden reviewed portions of the manuscript and provided helpful comments. Bulletin 1150 was published by the Office of Agricultural Communications, a unit of the Division of Agriculture, Forestry, and Veterinary Medicine at Mississippi State University. A Guide to the Ticks of Mississippi INTRODUCTION Members of the superfamily Ixodoidea, or ticks, Hard ticks have are acarines that feed obligately on the blood of mam - three motile life stages mals, amphibians, reptiles, and birds. Ticks have (Figure 3A). Some significant medical and veterinary importance, and ticks complete their knowledge of species present in a given area is impor - development on only tant to physicians, veterinarians, wildlife biologists, one or two hosts, but and farmers of livestock. most Mississippi ticks The two major families of ticks recognized in have a three-host life North America (Figure 1) are Ixodidae (hard ticks) cycle. A fully fed and Argasidae (soft ticks). Hard ticks have a hard female tick drops from scutum on top of their bodies and display obvious the host animal to the sexual dimorphism (Figure 2); the blood-fed females ground and lays from are capable of enormous expansion (Color Figure 1). 5,000 to 18,000 eggs. Their mouthparts are anterior and visible from dorsal The eggs hatch in about view. Soft ticks lack a hard scutum and sexual 35 days into a six- Color Figure 1. dimorphism and are mainly adapted for feeding rap - legged larva (seed tick Engorged female tick. idly and leaving the host promptly. Their mouthparts stage), which feeds pre - are generally subterminal and not visible from a dor - dominantly on small animals. The fully fed seed ticks sal view. drop to the ground and transform into eight-legged nymphs. These nymphs seek an animal host and likewise feed and drop to the ground. They then molt into the adult stage, thus complet - ing the life cycle. The biology of soft ticks dif - fers from that of hard ticks. Adult soft ticks feed and lay eggs repeat - edly, whereas hard ticks feed once and then lay eggs. Argasid females may feed and lay eggs several times, but they lay fewer eggs than do hard ticks. Also, soft tick species may undergo several nymphal SOFT TICK HARD TICK molts before reaching the adult A B stage (Figure 3B). Figure 1. Dorsal view of argasid (A) and ixodid (B) ticks (From USAF Publ. USAFSAM-SR-89-2). Mississippi Agricultural and Forestry Experiment Station 1 This bulletin summarizes the knowledge on ticks occurring in Mississippi. Many of the distribu - tion records used to generate this list of species are the result of extensive collecting conducted by the senior author from 1982 to 2004 throughout much of the state (Goddard and Norment 1983a, 1983b; Goddard 1986, 1992, 1993; Jackson and Goddard 1995; Jackson et al. 1996, Goddard 1997a, 2002a). In addition, several projects conducted by wildlife researchers have cited tick records Scutum from Mississippi (Prestwood 1968, FEMALE MALE Smith 1977, Andrews et al. 1980, Figure 2. Hard ticks showing sexual dimorphism Handrick 1981). Other medical or (From USAF Publ. USAFSAM-SR-89-2). veterinary projects have reported tick records from the state (Ward 1932, Archer 1946, representing 16 of the 19 species discussed are Carpenter et al. 1946, Philip and White 1955, Rhodes deposited in the Mississippi Entomological Museum or and Norment 1979, Nause and Norment 1984, Norment in the National Tick Collection (originally, Rocky et al. 1984, Goddard et al. 2003). The collection records Mountain Laboratory specimens). Three species have and literature show 19 tick species as occurring or hav - been reported for which specimens have not been ing occurred in Mississippi. Voucher specimens examined by the authors or verified as valid. A B Figure 3. Motile life stages of hard ticks (A) and soft ticks (B) (From USAF Publ. USAFSAM-SR-89-2). 2 A Guide to the Ticks of Mississippi TICKS AND HUMAN DISEASE has been widely known for some time that 1–3% of Lyme disease, mLoyrme eacDcuisraetealsye termed Lyme borre - lone star ticks, , carry spiro - liosis (LB), is caused by the spirochete, chetes similar tAomblyomma ame.riTcahneurem fore, cases of , and is a systemic illness with manyBcolrinreicliaa l LB-like illness inBt.hebusrogudtohrefaesrti ern and south-central mbuarngidfeosrtfaetriions. It occurs in temperate zones over much U.S. could be caused by this new spirochete (or others) of the world (Goddard 1997c). Although rarely fatal, the and not by . At least one case of erythema disease may be long and debilitating with heart, nerve, migrans haBs .bbeuerngcdaoursfeerdi by a spirochete called and joint involvement (Burrascano 1989). Initial symp - (James et al. 2001). B. lon - toms include a flu-like syndrome with headache, stiff estari neck, pain in the joints and muscles, a generalized feel - ing of weakness, and low-grade fever. Often, a RockRy oMcokuyntMaionusnpotattiend Sfepvoertt(eRdMFSeFv)eisr the most more-or-less circular, painless rash called erythema frequently reported rickettsial disease in the U.S. with migrans (EM) is present at the bite site. The EM lesion about 600 cases reported each year (CDC 2001). Many is often said to be the hallmark sign for LB, although not more cases probably occur but are unreported. People all patients develop it. EM lesions may steadily increase with RMSF usually show the classic triad of RMSF in size with subsequent central clearing, resembling a features — fever, rash, and history of tick bite. Other bull’s-eye. Untreated EM and associated symptoms usu - symptoms are weakness, severe headache, chills, and ally resolve in 3 to 4 weeks. However, the disease often body aches. Sometimes gastrointestinal symptoms such spreads throughout the body within weeks or months, as abdominal pain and diarrhea are reported. The rash, resulting in cardiac, neurologic, and joint manifestations appearing on about the third day, usually begins on the that may last for years. The number of reported LB extremities and then spreads to the rest of the body. cases in the U.S. continues to increase annually. There However, there have been confirmed cases of RMSF were 23,763 cases reported to the Centers for Disease without rash. Mental confusion, coma, and death may Control and Prevention (CDC) during 2002 (CDC occur in severe cases. The mortality rate is about 20% 2004). In the U.S., the vast majority of cases are from if untreated and 4% if treated. the northeastern and north-central states. Only about 11- 20 cases of LB are reported in Mississippi annually, although these are usually not officially confirmed. Lyme borreliosis is transmitted by tick bite. In the U.S., is the primIxaorydevsecstcoarpiunlatrhies East, and in the West. IOxothdeers tpicakcifsipceucs ies may be involved in the ecol - ogy of Lyme borreliosis in the U.S. Alternatively, there may be several, as-of-yet undescribed species that cause LyBmorer-elilkiae illness. In the southern U.S., researchers have doubted for several years whether reports of an LB-like illness Figure 4. Example of tick-borne disease cycle: are actually true LB. Also, it Rocky Mountain spotted fever. Mississippi Agricultural and Forestry Experiment Station 3 The agent of RMSF circulates in nature among small other two, but thus far, has only been identified in a few mammals (an example of a tick-borne disease life cycle patients, most of whom were immune compromised. is given in Figure 4) and is usually transmitted to people Therefore, much is yet unknown about human infection by the bite of an infected tick, although it is possible for with this agent. a person to get the disease while manually de-ticking Clinical and laboratory manifestations of infection dogs when infectious fluids get on the skin. Not all tick with HME or HGA are similar (Goddard 1997b). The species are effective vectors of the rickettsia, and even in patient usually gets a fever, headache, body aches, and the vector species, not all ticks are infected. Generally, progressive leukopenia (low white cell count). only 1% to 5% of vector ticks in an area are infected. Sometimes there is a cough, gastroenteritis, or meningi - Several tick vectors may transmit RMSF organisms, but tis. Rarely is there a rash, so ehrlichiosis is sometimes the primary one in the eastern U.S. is the American dog called “spotless” Rocky Mountain spotted fever. Illness tick, (Burgdorfer 1975). Ticks due to HME is thought by some to be milder than with are ofDteenrmbraocuegnhtotrinvtoarcialobsieliscontact with people via pet HGA based on reported fatality rates of 2–5% and dogs or cats (dog ticks may also feed on cats). 7–10% for HME and HGA, respectively. Ehrlichiosis is transmitted to humans via the bite of an infected tick. HME, which primarily occurs within OTtheerre SarpeostetveedraFl eovtheerrGhuromuapn Rdiiscekaseetstsciaousseds by the geographic distribution of the lone star tick, spotted fever group rickettsias, including rickettsialpox , seems to have a close associ - and Mediterranean spotted fever. In the southern U.S., a aAtmiobnlywoimthmtahaatmtiecrkicanndum the white-tailed deer. However, new spotted-fever-like disease called American bouton - detection of the HME agent in other tick vectors and a neuse fever, transmitted by , few cases outside the distribution of the lone star tick was recently discovered thatAcmaubslyeosmfmevaer,mahceuadlaatcuhm e, suggests that additional vectors occur.