| Ticks | |
| American dog tick (Dermacentor variabilis) | Q fever (Coxiella burnetii) |
| Rocky Mountain spotted fever (Rickettsia rickettsii); most common in the southeastern United States |
| Tick paralysis (toxin) |
| Tularemia (Francisella tularensis) |
| Black-legged or deer tick (Ixodes scapularis) and western black-legged tick (Ixodes pacificus) | Babesiosis (Babesia microti), a parasitic disease mimicking malaria in the northeastern and upper midwestern United States (I. scapularis only) |
| Human granulocytic anaplasmosis (formerly human granulocytic ehrlichiosis) |
| Lyme disease (Borrelia burgdorferi) |
| Brown dog tick (Rhipicephalus sanguineus) | Q fever |
| Rocky Mountain spotted fever |
| Lone Star tick (Amblyomma americanum) | Alpha-gal sensitivity (red meat allergy) |
| Human monocytic ehrlichiosis caused by Ehrlichia chaffeensis |
| Q fever |
| Southern tick-associated rash illness or Masters disease, a southern Lyme disease–like illness with rash, previously thought to be caused by Borrelia lonestari (etiology still uncertain) |
| Tularemia |
| Pacific Coast tick (Dermacentor occidentalis) | 364D rickettsiosis (Rickettsia phillipi, proposed), newly identified in California |
| Rocky Mountain spotted fever |
| Tularemia |
| Rocky Mountain wood tick (Dermacentor andersoni) | Colorado tick fever (orbivirus) |
| Potential vector of Powassan encephalitis and Q fever |
| Rocky Mountain spotted fever |
| Tick paralysis (toxin) |
| Tularemia |
| Soft ticks (Ornithodoros spp.), such as Pajaroello tick (Ornithodoros coriaceus) | Pajaroello tick bites of the southwestern United States are associated with pain and localized necrosis, probably mediated by a toxin |
| Relapsing fever (Borrelia spp.) in the western United States |
| Woodchuck tick (Ixodes cookei) | Powassan virus (Powassan encephalitis), a tick-borne encephalitis found in northern United States and Canada |
| Mites and fleas | |
| House mouse mites (Liponyssoides sanguineus) | Rickettsial pox (Rickettsia akari) |
| Various fleas | Cat flea typhus or flea-borne spotted fever (Rickettsia felis) |
| Cat-scratch disease (Bartonella henselae), transmitted between cats by fleas |
| Murine typhus (Rickettsia typhi) |
| Plague (Yersinia pestis), endemic to western United States with occasional human cases from contact with rodent fleas |
| Tularemia |
