Contributor: Gordon K. Klintworth
Numerous human infections are associated with arthropods. Some are involved in the transmission of viral infection (arboviral disease, Colorado tick fever, yellow fever), bacterial infection (Lyme disease, bartonellosis, relapsing fever), rickettsial infection (epidemic typhus, trench fever, endemic typhus, Rocky Mountain spotted fever), and protozoal infection (malaria, leishmaniasis, babesiosis). Other arthropods (diptera [diptera disease], fleas, mites, and lice [louse infestation]) can cause ocular disease by themselves.
Flies. Some flies are vectors in the transmission of several infectious diseases (trachoma) (Musca domestica), loiasis (blood-sucking mangrove flies (Chrysops sp.), onchocerciasis (blackflies, Simulium sp), trypanosomiasis (tsetse flies), leishmaniasis (sandfly, usually Plebotomus spp.), bartonellosis (nocturnal sandfly, Lutzomyia verrucarum) and some other bacterial infections (Musca domestica). The larvae of certain flies invade the skin and ocular tissue to cause various types of myiasis (dermal myisais [myiasis - dermal], orbital myiasis [myiasis - orbital], ocular myiasis (ophthalmomyiasis) which may involve external structures of the eye (ophthalmomyiasis externa) or internal parts (ophthalmomyiasis interna).
Lice. Rickettsial infection is spread by the human body louse (epidemic typhus, trench fever), rat louse (endemic typhus),  Relapsing fever is transmitted by an infected human louse (Pediculus humanus corporis).
Ticks. The wood tick or dog tick transmit Rocky Mountain spotted fever, Boutonneuse fever, Q fever ( Haemataphysalis humerosa, and Dermcenter andersoni), Lyme disease (several species of the genus Ixodes). Endemic relapsing fever is transmitted by the bite of an infected tick from rodents and other animals. Ticks also transmit Colorado tick fever, tularemia, ehrlichiosis, and Lyme disease.
Fleas. Fleas are carriers of diseases, such as the plague and murine typhus. They transmit pathogens by bites or feces.
Mites. Mites spread scrub typhus (chigger).
Mosquitoes. Mosquitoes spread malaria (Anopheles), dirofilariasis (Culex, Aedes and Anopheles), yellow fever (Aedes aegypti), dengue fever (Aedes aegypti). The life cycle of some parasites (Dracunculus medinensis [dracunculiasis], Gnathostoma spinigerum [gnathostomiasis], Spirometra [sparganosis] involves a stage in crustaceans and humans can be become infected by the parasite after ingesting the infected crustacean or in the case of sparganosis also by ingesting contaminated water or applying the flesh from infected frogs to open wounds and inflammed eyes as a poultice in regions of Southeast Asia. The hairs of a caterpillar can cause significant damage to the eye as in ophthalmia nodosa. Some arthropods (bee, wasp, scorpion) cause lesions in the eyelid, conjunctiva or cornea by their stings.  The hairs of a tarantula can enter the superficial tissues of the eye and cause an inflammatory reaction.