​Argulus sp. or fish lice.  They are crustacean ectoparasites of fish not uncommonly found to infest freshwater fish. They have a jelly-like appearance, two compound eyes, and a disc-shaped wide carapace covering most of their rounded body. All life stages are parasitic and use a stylet to pierce their fish host, secrete digestive enzymes, and feed on body fluids. Adults are approximately 3-7mm in length and 2-4mm wide and have paired ventral suckers near their mouth to help attach to the fish. Females leave the host to lay rows of eggs on vegetation and hard surfaces in the environment before returning to the host to feed.
 
Infestations on fish can cause local inflammation at sites of attachment, anemia, scale loss, behavior changes (e.g., reduced feeding, rubbing on surfaces), and secondary bacterial infections at the attachment sites. Because of their rapid reproduction rate, infestations can quickly cause morbidity and mortality in captive environments. Argulus spp. can also serve as a mechanical vector or intermediate host for several fish diseases, including spring viremia of carp and several nematode species.
 
Treatment can be challenging and must target each life stage throughout their life cycle, which may take 30 to 60 days. Treatment options include multi-doses of organophosphates, potassium permanganate, or chitin synthesis inhibitors including pesticides such as diflubenzuron.

Foleyella furcata, belongs to the family Onchocercidae. It is transmitted by mosquitoes which ingest microfilaria from infected hosts (image 4). In the mosquito they develop into the infective stage and perpetuate the cycle when biting a naïve host. Adults commonly develop in the body fat of chameleons.

​Notoedres cati, a contagious burrowing mite from the family Sarcoptidae.  It infests cats, wild felids and other animals such as rabbits, foxes and dogs.  Infestations with this mite produce alopecia, pruritus, crusting and self-excoriation.  Usually, lesions are restricted to the auricles, head, face, neck, and shoulders.
Differentiation from Sarcoptes scabiei can be done according to location of anus, in N. cati is dorsal (large arrow), while in S. scabei is in a terminal position. Additionally, N. cati dorsal spines are smaller and more rounded when compared to S. scabei (small arrows).

​Amblyomma sabanerae, adult female.  These ticks have been reported from Mexico and Central America, infesting turtles of the genus Rhinoclemmys.  Each adult tick can ingest more than 2 ml of blood.

​Mycoptes musculinus male and Hymenolepis diminuta egg.
Mites of the family Myocoptidae are inhabitants of mice hair, while Hymenolepis diminuta is a cestode of rodents.  Both are spurious parasites of the snake.
The legs IV of the M. musculinus males are modified for clasping the female during copulation. These mites are commonly distributed on the dorsum or mice, feeding on debris without invading the skin. Transmission occurs by direct contact and some mice develop pruritus and alopecia.
Himeloplis diminuta is a common cestode of rodents that requires a beetle as intermediate host.  Infections are commonly subclinical.

​Subcutaneous Amblyomma americanum ticks (females, males, and nymphs).
Ticks are obligate ectoparasites that spend part of their life attached to their hosts. They have mouthparts with chelicerae that pierce through the skin of the host. Attachment is facilitated by the tubular hypostome and a secreted cement or latex-like compound that attaches the tick to the host until the feeding is complete.
Although most of the subcutaneous cases of subcutaneous ticks have described Ixodes spp., previous reports from Missouri and Arkansas have described the finding of intradermal infestations of red foxes (Vulpes vulpes) with Amblyomma americanum ticks. 
Other descriptions from other countries have mainly been from foxes, golden jackals, domestic and racoon dogs; and a single report also described the finding in a human. The reasons to explain the unusual location on these host are not clear yet, indications seem to suggest that immune response of canids may play a role.