''Leucocytozoon caulleryi'' is a species of the genus '' Leucocytozoon'', a genus of parasitic alveolates. This species has both insect (''

Culicoides ''Culicoides'' is a genus of biting midges in the family Ceratopogonidae. There are over 1000 species in the genus,Connelly, C. RBiting midges: ''Culicoides'' spp.Featured Creatures, Entomology and Nematology Department, University of Florida IF ...

'' species) and vertebrate (

bird Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...

s) hosts.

Description

History

This species was originally described by Mathis and Leger in 1909. The species was also described by Akiba in Japan in 1958. A second species - ''Leucocytozoon schufneri'' - was described by Prowazek in 1912 also in the chicken. This is now considered to be a synonym. This species has been classified into the subgenus '' Akiba'' because of its vector: other species in the genus are transmitted by species of the genus ''

Simulium ''Simulium'' is a genus of Black_fly, black flies, which may transmit diseases such as onchocerciasis (river blindness). It is a large genus with almost 2,000 species and 38 subgenus, subgenera. The flies are pool feeders. Their saliva, wh ...

''.

Life cycle

The parasite is transmitted by the bite of its vector. On infection of a vertebrate host, the parasites enter the blood stream and spread through the body. They invade the

endothelial cell The endothelium (: endothelia) is a single layer of squamous endothelial cells that line the interior surface of blood vessels and lymphatic vessels. The endothelium forms an interface between circulating blood or lymph in the lumen and th ...

s in a number of organs. These grow into multinucleated masses - megaloschizonts. This first round of schizonts give rise to the first generation of merozoites. This first generation of merozoites invade new endothelial cells and give rise to a second generation of schizonts. After a number of cell divisions these in turn give rise to the second generation of

merozoite Apicomplexans, a group of intracellular parasites, have life cycle stages that allow them to survive the wide variety of environments they are exposed to during their complex life cycle. Each stage in the life cycle of an apicomplexan organism i ...

s which in their turn infect

erythrocyte Red blood cells (RBCs), referred to as erythrocytes (, with -''cyte'' translated as 'cell' in modern usage) in academia and medical publishing, also known as red cells, erythroid cells, and rarely haematids, are the most common type of blood ce ...

s and

leukocyte White blood cells (scientific name leukocytes), also called immune cells or immunocytes, are cells of the immune system that are involved in protecting the body against both infectious disease and foreign entities. White blood cells are genera ...

s. Within the erythrocytes or leukocytes, the merozoites develop into

gametocyte A gametocyte is a eukaryotic germ cell that divides by mitosis into other gametocytes or by meiosis into gametids during gametogenesis. Male gametocytes are called ''spermatocytes'', and female gametocytes are called ''oocytes''. Development T ...

s. Once ingested by a vector male and female gametocytes fuse and give rise to a zygote. The zygote invades the body of the vector, undergoes a series of cell divisions resulting in motile sporozoites that invade the salivary glands of the vector. Early schizonts are spherical or ovoid and 30-35

micrometers The micrometre (Commonwealth English as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American English), also commonly known by the non-SI term micron, is a unit of length in the International System ...

(μm) in diameter.Isobe T, Akiba K (1900) Early schizonts of ''Leucocytozoon caulleryi''. J Parasitol 76(4):587-589 Gametocytes are round and measure 15.0 to 15.5 μm in diameter.

Geographic distribution

This species is found in

Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...

Kazakhstan Kazakhstan, officially the Republic of Kazakhstan, is a landlocked country primarily in Central Asia, with a European Kazakhstan, small portion in Eastern Europe. It borders Russia to the Kazakhstan–Russia border, north and west, China to th ...

Malaysia Malaysia is a country in Southeast Asia. Featuring the Tanjung Piai, southernmost point of continental Eurasia, it is a federation, federal constitutional monarchy consisting of States and federal territories of Malaysia, 13 states and thre ...

, the

Philippines The Philippines, officially the Republic of the Philippines, is an Archipelagic state, archipelagic country in Southeast Asia. Located in the western Pacific Ocean, it consists of List of islands of the Philippines, 7,641 islands, with a tot ...

Singapore Singapore, officially the Republic of Singapore, is an island country and city-state in Southeast Asia. The country's territory comprises one main island, 63 satellite islands and islets, and one outlying islet. It is about one degree ...

Taiwan Taiwan, officially the Republic of China (ROC), is a country in East Asia. The main geography of Taiwan, island of Taiwan, also known as ''Formosa'', lies between the East China Sea, East and South China Seas in the northwestern Pacific Ocea ...

and

Thailand Thailand, officially the Kingdom of Thailand and historically known as Siam (the official name until 1939), is a country in Southeast Asia on the Mainland Southeast Asia, Indochinese Peninsula. With a population of almost 66 million, it spa ...

Clinical features and host pathology

This species infects chickens ('' Gallus gallus domesticus''), guinea fowl and pheasants. After infection schizongony occurs in the

adrenal The adrenal glands (also known as suprarenal glands) are endocrine glands that produce a variety of hormones including adrenaline and the steroids aldosterone and cortisol. They are found above the kidneys. Each gland has an outer cortex which ...

brain The brain is an organ (biology), organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It consists of nervous tissue and is typically located in the head (cephalization), usually near organs for ...

intestine The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The tract is the largest of the body's systems, after the cardiovascular system. T ...

kidney In humans, the kidneys are two reddish-brown bean-shaped blood-filtering organ (anatomy), organs that are a multilobar, multipapillary form of mammalian kidneys, usually without signs of external lobulation. They are located on the left and rig ...

liver The liver is a major metabolic organ (anatomy), organ exclusively found in vertebrates, which performs many essential biological Function (biology), functions such as detoxification of the organism, and the Protein biosynthesis, synthesis of var ...

muscle Muscle is a soft tissue, one of the four basic types of animal tissue. There are three types of muscle tissue in vertebrates: skeletal muscle, cardiac muscle, and smooth muscle. Muscle tissue gives skeletal muscles the ability to muscle contra ...

ovaries The ovary () is a gonad in the female reproductive system that produces ova; when released, an ovum travels through the fallopian tube/oviduct into the uterus. There is an ovary on the left and the right side of the body. The ovaries are endocr ...

pancreas The pancreas (plural pancreases, or pancreata) is an Organ (anatomy), organ of the Digestion, digestive system and endocrine system of vertebrates. In humans, it is located in the abdominal cavity, abdomen behind the stomach and functions as a ...

spleen The spleen (, from Ancient Greek '' σπλήν'', splḗn) is an organ (biology), organ found in almost all vertebrates. Similar in structure to a large lymph node, it acts primarily as a blood filter. The spleen plays important roles in reg ...

thymus The thymus (: thymuses or thymi) is a specialized primary lymphoid organ of the immune system. Within the thymus, T cells mature. T cells are critical to the adaptive immune system, where the body adapts to specific foreign invaders. The thymus ...

and

trachea The trachea (: tracheae or tracheas), also known as the windpipe, is a cartilaginous tube that connects the larynx to the bronchi of the lungs, allowing the passage of air, and so is present in almost all animals' lungs. The trachea extends from ...

. Typical pathology includes the presence of the schizonts and the surrounding granulomata, haemorrhages, oedema and pressure atrophy in the oviducts. Infected chickens are anaemic, have pale combs and diarrhoea. Egg production may be reduced and the egg shells may be softer than normal. Chickens who survive the infection appear to be resistant to re infection. A vaccine based on a recombinant protein is available.Ito A, Gotanda T (2004) Field efficacy of recombinant R7 vaccine against chicken leucocytozoonosis. J Vet Med Sci 66(5):483-487 This disease is also known as

Bangkok Bangkok, officially known in Thai language, Thai as Krung Thep Maha Nakhon and colloquially as Krung Thep, is the capital and most populous city of Thailand. The city occupies in the Chao Phraya River delta in central Thailand and has an estim ...

haemorrhagic disease.

Vectors

Known vectors of this parasite include '' Culicoides arakawae'' Arakawa 1910.

Diagnosis

Blood smears can be performed to identify the parasite in the red blood cells.

ELISA The enzyme-linked immunosorbent assay (ELISA) (, ) is a commonly used analytical biochemistry assay, first described by Eva Engvall and Peter Perlmann in 1971. The assay is a solid-phase type of enzyme immunoassay (EIA) to detect the presence of ...

testing can be used for antigen or antibody testing.''Leucocytozoon caulleryi''
reviewed and published by

WikiVet WikiVet is a wiki of veterinary content based on the MediaWiki platform. The website is a collaborative initiative between various veterinary schools, and its content covers the entire veterinary curriculum. WikiVet is part of the WikiVet Educatio ...

, accessed 12 October 2011.

Treatment and prevention

Treatment is usually ineffective. In-feed

pyrimethamine Pyrimethamine, sold under the brand name Daraprim among others, is a medication used with leucovorin (leucovorin is used to decrease side effects of pyrimethamine; it does not have intrinsic anti-parasitic activity) to treat the parasitic disea ...

and sulfadimethoxine can help prevent the disease. Prevention is by control of the infecting vectors but is often difficult to implement.

References

{{Taxonbar, from=Q4700880 Haemosporida Apicomplexa species Parasites of Diptera Parasites of birds