Neospora

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Neospora
Neospora caninum (5256961091).jpg
Neospora caninum
Scientific classification Red Pencil Icon.png
Clade: SAR
Infrakingdom: Alveolata
Phylum: Apicomplexa
Class: Conoidasida
Order: Eucoccidiorida
Family: Sarcocystidae
Genus: Neospora
Species

Neospora is a single celled parasite of livestock and companion animals. It was not discovered until 1984 in Norway, where it was found in dogs. Neosporosis, the disease that affects cattle and companion animals, has a worldwide distribution. Neosporosis causes abortions in cattle and paralysis in companion animals. It is highly transmissible and some herds can have up to a 90% prevalence. Up to 33% of pregnancies can result in aborted fetuses on one dairy farm. In many countries this organism is the main cause of abortion in cattle. [1] Neosporosis is now considered as a major cause of abortion in cattle worldwide. Many reliable diagnostic tests are commercially available. Neospora caninum does not appear to be infectious to humans. In dogs, Neospora caninum can cause neurological signs, especially in congenitally infected puppies, where it can form cysts in the central nervous system.

Contents

Genome

The genome of Neospora caninum has been sequenced. [2] The results suggest a European origin for this parasite.

Effects of disease

Neospora caninum is a major pathogen of cattle and dogs that occasionally causes clinical infections in horses, goats, sheep, and deer as well. The domestic dog is the only known definitive host for N. caninum. In cattle, N. caninum is a major cause of bovine abortion in many countries and is one of the most efficiently transmitted parasites with up to 90% of some bovine herds infected. N. caninum causes abortion in both beef and dairy cattle. Another important factor is the gestational age and hence immunocompetence of the fetus at the time of infection. [3] Early in gestation, N. caninum infection of the placenta and subsequently the fetus usually proves fatal, whereas infection occurring in mid to late pregnancy may result in the birth of a congenitally infected but otherwise healthy calf. Recent studies have broadened the list of known intermediate hosts to include birds. N. caninum has recently been found to infect domestic chickens and house sparrows ( Passer domesticus ) which may become infected after ingesting parasite oocysts from the soil. [4] The presence of birds in cattle pastures has been correlated to higher infection rates in cattle. [5] Birds may be an important link in the transmission of N. caninum to other animals.

Epidemiology

The life cycle is similar to Toxoplasma . An infected dog will pass the oocysts through its feces and infect food or water. A cow or other animal will then up take the parasite. The parasite will undergo asexual reproduction in the animal's muscle until it is eaten by a dog. There, sexual reproduction will occur and oocysts will be created and passed through the feces. Dogs are often the definitive host but can act as an intermediate host as well. Cows are usually the intermediate host. No horizontal cow-to-cow transmission have been shown, although salival interactions have been suggested. Vertical transmission can occur when an infected cow gives birth to an infected calf—the calf survives the infection and grows into an adult. Vertical route is the major route of transmission in cattle and is extremely efficient as the rate of transmission is usually between 80 and 100%. [6] A heifer calf that is born congenitally infected is capable of transmitting the infection to the next generation when she becomes pregnant, thus maintaining the infection in the herd. Transplacental transmission in cattle is considered the major route of transmission. The life cycle is typified by three infectious stages: tachyzoites, tissue cysts, and oocysts [7] Tachyzoites and tissue cysts are the stages found in the intermediate hosts, and they occur intracellularly.

Detection of disease

Detection: the presence of cerebral and cardiac lesions can be seen on aborted bovine fetuses originating from a single farm. The parasite is identified in the tissues of many bovine aborted fetuses but also of stillborn calves and, rarely, of clinically affected newborn calves. The diagnosis of the infection is assisted through histopathology and immunohistochemical examination of aborted fetuses and serologic testing of cattle for evidence of infection. [8] The abortion is the only clinical sign and can occur from the third month of pregnancy and onwards. Most of the abortions take place between the 5th and 6th months of pregnancy [9] The fetus is either resorbed, autolyzed, mummified, stillborn, born alive with clinical signs, or born clinically normal but chronically infected. At calving, infected calves may be clinically normal or may have neurologic signs, be underweight or unable to stand.

Prevention and control

Embryo transfer is recommended as a method of reproduction to reduce the chances of contracting the disease, as long as the disease status of the donor cow is checked. It is not recommended to rebreed heifers or cows that have this disease. Seropositive animals should be culled. To prevent horizontal transmission it is important to prevent the contamination of feed and water via the shedding of oocysts by dogs and possibly other canids like the fox. These animals should not have access to animal premises although this might be difficult to achieve. There are no drugs or vaccines available yet to prevent or control the disease.

Related Research Articles

Toxoplasmosis Parasitic disease

Toxoplasmosis is a parasitic disease caused by Toxoplasma gondii, an apicomplexan. Infections with toxoplasmosis usually cause no obvious symptoms in adults. Occasionally, people may have a few weeks or months of mild, flu-like illness such as muscle aches and tender lymph nodes. In a small number of people, eye problems may develop. In those with a weak immune system, severe symptoms such as seizures and poor coordination may occur. If a woman becomes infected during pregnancy, a condition known as congenital toxoplasmosis may affect the child.

<i>Toxoplasma gondii</i> Type of protozoan parasite

Toxoplasma gondii is an obligate intracellular parasitic protozoan eukaryote that causes the infectious disease toxoplasmosis. Found worldwide, T. gondii is capable of infecting virtually all warm-blooded animals, but felids, such as domestic cats, are the only known definitive hosts in which the parasite may undergo sexual reproduction.

Brucellosis Human and animal disease

Brucellosis is a highly contagious zoonosis caused by ingestion of unpasteurized milk or undercooked meat from infected animals, or close contact with their secretions. It is also known as undulant fever, Malta fever, and Mediterranean fever.

Coccidia A subclass of protists

Coccidia (Coccidiasina) are a subclass of microscopic, spore-forming, single-celled obligate intracellular parasites belonging to the apicomplexan class Conoidasida. As obligate intracellular parasites, they must live and reproduce within an animal cell. Coccidian parasites infect the intestinal tracts of animals, and are the largest group of apicomplexan protozoa.

Coccidiosis is a parasitic disease of the intestinal tract of animals caused by coccidian protozoa. The disease spreads from one animal to another by contact with infected feces or ingestion of infected tissue. Diarrhea, which may become bloody in severe cases, is the primary symptom. Most animals infected with coccidia are asymptomatic, but young or immunocompromised animals may suffer severe symptoms and death.

<i>Eimeria</i> Genus of single-celled organisms

Eimeria is a genus of apicomplexan parasites that includes various species capable of causing the disease coccidiosis in animals such as cattle, poultry, dogs, cats, and smaller ruminants including sheep and goats. Eimeria species are considered to be monoxenous because the life cycle is completed within a single host, and stenoxenous because they tend to be host specific, although a number of exceptions have been identified. Species of this genus infect a wide variety of hosts. Thirty-one species are known to occur in bats (Chiroptera), two in turtles, and 130 named species infect fish. Two species infect seals. Five species infect llamas and alpacas: E. alpacae, E. ivitaensis, E. lamae, E. macusaniensis, and E. punonensis. A number of species infect rodents, including E. couesii, E. kinsellai, E. palustris, E. ojastii and E. oryzomysi. Others infect poultry, rabbits and cattle. For full species list, see below.

<i>Neospora caninum</i> Species of Conoidasida in the apicomplex phylum

Neospora caninum is a protozoa that was identified as a species in 1988. Prior to this, it was misclassified as Toxoplasma gondii due to structural similarities. The genome sequence of Neospora caninum has been determined by the Wellcome Trust Sanger Institute and the University of Liverpool. Neospora caninum is an important cause of spontaneous abortion in infected livestock.

<i>Campylobacter fetus</i> Species of bacterium

Campylobacter fetus is a rod-shaped, gram-negative species of bacteria within the genus Campylobacter of phylum Proteobacteria. Identification of C. fetus species in infected animals or people is routinely performed by culture on blood or cefoperazone deoxycholate agar. Subspecies of C. fetus commonly causes reproductive disease in ruminants and gastrointestinal disease in humans. Transmission of C. fetus subspecies venerealis occurs mainly through venereal contact while transmission of C. fetus subspecies fetus occurs mainly through ingestion of bacteria in a contaminated environment. Infertility in cattle and abortion in sheep are common outcomes of infection associated with C. fetus subspecies venerealis and C. fetus subspecies fetus, respectively. Disease in humans occurs through zoonotic transmission of C. fetus mainly via ingestion of contaminated food or water sources. C. fetus can be diagnosed with polymerase chain reaction assays, enzyme linked immunosorbent assays and vaginal mucus agglutination testing. As vaccines are typically not efficient in preventing future spread, infected bulls are often culled. Human infections may be treated with erythromycin as antimicrobial resistance has been emerging for the fluoroquinolones.

Bovine alphaherpesvirus 1 (BoHV-1) is a virus of the family Herpesviridae and the subfamily Alphaherpesvirinae, known to cause several diseases worldwide in cattle, including rhinotracheitis, vaginitis, balanoposthitis, abortion, conjunctivitis, and enteritis. BoHV-1 is also a contributing factor in shipping fever, also known as bovine respiratory disease (BRD). It is spread horizontally through sexual contact, artificial insemination, and aerosol transmission and it may also be transmitted vertically across the placenta. BoHV-1 can cause both clinical and subclinical infections, depending on the virulence of the strain. Although these symptoms are mainly non-life-threatening it is an economically important disease as infection may cause a drop in production and affect trade restrictions. Like other herpesviruses, BoHV-1 causes a lifelong latent infection and sporadic shedding of the virus. The sciatic nerve and trigeminal nerve are the sites of latency. A reactivated latent carrier is normally the source of infection in a herd. The clinical signs displayed are dependent on the virulence of the strain. There is a vaccine available which reduces the severity and incidence of disease. Some countries in Europe have successfully eradicated the disease by applying a strict culling policy.

<i>Sarcocystis</i> Genus of protists in the apicomplex phylum

Sarcocystis is a genus of protozoan parasites, the majority of species infecting mammals, and some infecting reptiles and birds.

Bovine viral diarrhea Significant economic disease of cattle caused by two species of Pestivirus

Bovine viral diarrhea (BVD), bovine viral diarrhoeaor mucosal disease, and previously referred to as bovine virus diarrhea (BVD), is an economically significant disease of cattle that is found in the majority of countries throughout the world. Worldwide reviews of the economically assessed production losses and intervention programs incurred by BVD infection have been published. The causative agent, bovine viral diarrhea virus (BVDV), is a member of the genus Pestivirus of the family Flaviviridae.

<i>Tritrichomonas foetus</i>

Tritrichomonas foetus is a species of single-celled flagellated parasites that is known to be a pathogen of the bovine reproductive tract as well as the intestinal tract of cats. In cattle, the organism is transmitted to the female vagina and uterus from the foreskin of the bull where the parasite is known to reside. It causes infertility, and, at times, has caused spontaneous abortions in the first trimester. In the last ten years, there have been reports of Tritrichomonas foetus in the feces of young cats that have diarrhea and live in households with multiple cats. Tritrichomonas foetus looks similarly to Giardia and is often misdiagnosed for it when viewed under a microscope.

Mastitis in dairy cattle

Bovine mastitis is the persistent, inflammatory reaction of the udder tissue due to physical trauma or microorganisms infections. Mastitis, a potentially fatal mammary gland infection, is the most common disease in dairy cattle in the United States and worldwide. It is also the most costly disease to the dairy industry. Milk from cows suffering from mastitis has an increased somatic cell count. Prevention and control of mastitis requires consistency in sanitizing the cow barn facilities, proper milking procedure and segregation of infected animals. Treatment of the disease is carried out by penicillin injection in combination with sulphar drug.

Bovine gammaherpesvirus 4 (BoHV-4) is a member of the Herpesviridae family. It is part of the subfamily Gammaherpesvirinae and genus Rhadinovirus. Infection is normally sub-clinical but can cause reproductive disease in cattle such as endometritis, vulvovaginitis and mastitis. Transmission is both vertical and horizontal. It can also be indirectly spread by fomites. Distribution is worldwide and the virus infects a range of ruminants, including bison, buffalo, sheep and goats.

Ungulate bocaparvovirus 1, formerly Bovine parvovirus (BPV), also known as Haemadsorbing enteric Virus, is a member of the parvovirus group, with three significant sub-species: BPV1, 2 and 3. BPV most commonly causes diarrhea in neonatal calves and respiratory and reproductive disease in adult cattle. The distribution of the virus is worldwide. Transmission is both vertical and horizontal. The virus is very resistant to chemical and physical challenges.

Demodex bovis, also known as the cattle follicle mite, usually causes demodicosis, or demodectic mange, in cattle. This disease is common in tropical areas and is not usually found in temperate environments. Demodicosis is characterized by the formation of papules and nodules over the cattle's skin. These lesions most commonly occur on the neck, shoulders, and armpit of cattle; however, sometimes they also appear on the udder. This condition is often found in cattle with increased stress from pregnancy or lactation. Natural and acquired immunity can cause a decrease in the number of mites infesting a cow, as well as decreasing the severity of a cow's symptoms.

Hammondia hammondi is a species of obligate heteroxenous parasitic alveolates of domestic cats. Intracellular cysts develop mainly in striated muscle. After the ingestion of cysts by cats, a multiplicative cycle precedes the development of gametocytes in the epithelium of the small intestine. Oocyst shedding persists for 10 to 28 days followed by immunity. Cysts in skeletal muscle measure between 100 and 340 μm in length and 40 and 95 μm in width. Some of the intermediate hosts develop low levels of antibody and some cross-immunity against Toxoplasma.

Eimeria zuernii is a species of the parasite Eimeria that causes diarrheic disease known as eimeriosis in cattle, and mainly affects younger animals. The disease is also commonly referred to as coccidiosis. The parasite can be found in cattle around the globe.

Beef cattle vaccination in Australia

Vaccinations for cattle involves the process of applying subcutaneous injections of biological microorganisms in a weakened state to help the immune system develop protection by providing active acquirement of immunity to a particular disease. Cattle are bovine livestock and are thus very susceptible to diseases. Vaccinations for cattle are widely used in the livestock industries of the Australian agriculture sector by farmers to prevent harmful and deadly diseases from infecting their livestock, avoiding any economical or biological harm. Farmed livestock industries account for 45% of the gross value of Australian agricultural output, beef cattle being the largest farmed livestock nationally with around 26.2 million head of cattle nationwide. The beef industry within Australia generates a gross value of approximately $8 billion AUD in beef exports and a total gross value of $11.4 billion in farm production (2017–18). Thus, vaccinations play a vital role in protecting, sustaining and growing the beef cattle industry in the Australian agriculture sector.

Eimeria bovis is a paraiste belonging to the genus Eimeria and is found globally. The pathogen can cause a diarrheic disease in cattle referred to as either eimeriosis or coccidiosis. The infection predominantly cause disease in younger animals.

References

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