Cytauxzoon felis

Cytauxzoon felis in erythrocytes

Cytauxzoonosis is parasite disease caused by parasitic protozoa Cytauxzoon felis and it was first reported in the USA in 1976. This genus was originally described in African grey duiker (Sylvicapra grimmia), but is now known to be common in felids including the domestic cat.

The domestic cat (Felis catus) has been considered an aberrant or dead-end host given the acute and fatal course of disease; however, there are reports of domestic cats surviving natural infection with and without treatment. The bobcat (Lynx rufus) is the natural host, typically experiencing subclinical infection and maintaining chronic parasitemia. Cytauxzoon felis infection has been reported in several other wild felids, such as cougars and panthers, in the absence of overt disease; however, a few lions and tigers have been reported to succumb to illness.

The parasites are transmitted by tick bite. After a cat or other host is bitten by an infected tick the parasites infect mononuclear phagocytes. Within these they undergo asexual reproduction (schizonts). As these leukocytes become engorged with schizonts, they line the lumens of veins and may causing obstruction of blood flow. The schizonts develop into merozoites which eventually cause host cell rupture and enter the blood. These intravascular merozoites infect variable numbers of erythrocytes.


Cellophane tape method

Clear tape containing lice applied to a microscopic slide

Cellophane or scotch tape is used to collect surface mites and fur mites, and lice infestations in animals. The tape is applied sticky side down to collect any white flakes or powdery looking material that is on the skin and hair shafts. It is acceptable to collect a few hairs in this manner to look for nits or organisms clinging to the hair shafts. The tape is applied sticky side down onto a microscopic slide. A drop of oil or water can be placed on the slide between the tape and the slide, but it is not necessary when collecting for large organisms such as lice.

Cellophane tape preparation is also used to detect pinworms, which occur in primates, horses, rabbits, and rodents. The eggs are collected by using the sticky side of the tape against the anus and anal folds. The tape is then applied sticky side down on the slide with a drop of water or oil to reveal the pinworm ova and examined microscopically.

Cymothoa exigua


Cymothoa exigua in fish mouth

Cymothoa exigua, or the tongue-eating louse, is a parasitic crustacean of the family Cymothoidae. This parasite enters fish through the gills, and then attaches itself at the base of the fish’s tongue. The female attaches to the tongue and the male attaches on the gill arches beneath and behind the female. Females are 8–29 millimetres (0.3–1.1 in) long and 4–14 mm (0.16–0.55 in) in maximum width. Males are approximately 7.5–15 mm (0.3–0.6 in) long and 3–7 mm (0.12–0.28 in) wide. The parasite destroys the fish’s tongue, and then attaches itself to the stub of what was once its tongue and becomes the fish’s new tongue.