Yesterday afternoon upon arriving at the hospital and doing one of many sweeps of the front area, I found my favorite kitten quartet missing. I soon found out that they’re with an employee because the poor babies have coccidia.
- Domain: Eukaryota
- Kingdom: Chromalveolata
- Superphylum: Alveolata
- Phylum: Apicomplexa
- Class: Conoidasida
- Subclass: Coccidia
- Order: Eucoccidiorida
This parasite has a one host life cycle. The Eimeria species has a single host, meaning you can’t infect a cow with chicken coccidia. The Cystoisospera species has also a single host but most can use a paratenic host. Dogs, cats, humans and other carnivore infecting coccidia use 2 hosts in their cycle. Coccidia is extremely host specific. It is also site specific once inside the host. Each species has specific a location in the intestine where it will develop or maybe even a specific part of a cell.
In terms of multiplication, coccidia are sexual OR asexual (schizogony). The sexual multiplication uses macrogamonts (female) and microgamonts (male). Upon fertilization, a zygote is produced that becomes an oocyst.
The oocyst is the environmentally stable cyst stage of the parasite. They are excreted unsporulated and sporulate once in the environment. The particular species of coccidia is identified based on the structure of the sporulated oocyst. Not all species are pathogenic and it is the sporozoites that actively invade cells. Excystation out of the oocyst and sporocyst occurs when the bile and trypsin in the stomach and intestine activate the sporozoites. The Eimeria species has 4 sporocysts with 2 sporozoites each while the Cystoisospera have 2 sporocysts with 4 sporozoites each.
This parasite follows a fecal-oral transmission (i.e. ingesting something contaminated by infected fecal material). This parasite is important in industries such cattle, poultry and swine. Pathogenicity (how severe the infection is) can depend on many factors such as:
- Species of coccidia
- Number of occysts ingested
- Age of animal
- Presence of immunosuppression
- Environmental conditions
The disease may result in:
- Weight loss
- Tissue destruction by rupture of infected cells (merozoites released)
- Vilous atrophy – malabsorption
- Hemorrhage – blood loss
Hopefully the kittens aren’t too heavily infected and will recover soon.
:: Information from this post is from my notes from an Introductory Parasitology class taught by Dr. Zajac at Virginia Tech ::
- Feline Immunodeficiency Virus (trushin.wordpress.com) – Introduced the Fantastic Four
- Parasite Terminology (trushin.wordpress.com)
- The Stages of Toxoplasma gondii (trushin.wordpress.com)