INTRODUCTION:

General Classification of coronovirus

Family- Coronaviridae [1]

Subfamily- Coronavirinae [3]

Order- Nidovirales [1]

Suborder: Cornidovirineae [2]

Genus- Coronovirus

Introduction of Coronavirus:

Coronavirusesare virus genera within the virus family Coronaviridae, order Nidovirales. Coronaviruses are well-established pathogens of humans and animals.[1] The name "coronavirus" is derived from the Latin corona, meaning crown or halo, and refers to how virions look under electron microscopy [3]

General Types of Coronavirus: -

1. Feline coronavirus

2. Canine coronavirus

3. Transmissible gastroenteritis coronavirus

4. Porcine epidermic diarrhoea coronavirus

5. Porcine haemagglutinating encephalomyelitis coronavirus

6. Bovine coronavirus

7. Severe acute respiratory

8. Infectious bronchitis coronavirus

9. Turkey Coronavirus

1) Feline coronavirus classification-

Realm-Riboviria [6]

Phylum-Incertae sedis [6]

Order-Nidovirales [6]

Family-Coronaviridae [1]

Genus-Alphacoronavirus [6]

Subgenus-Tegacovirus [6]

Species-Alphacoronavirus 1 [6]

Virus-Feline coronavirus [6}

A) General Introduction of Feline coronavirus:

Feline coronavirus (FCoV) is a positive-stranded RNA virus that is infectious to cats worldwide. This virus is part of the species Alphacoronavirus 1 of the genus Alphacoronavirus belonging to the virus family Coronaviridae. Alphacoronavirus 1 also includes the canine coronavirus (CCoV) and the porcine transmissible gastroenteritis coronavirus (TGEV)[6]

Feline coronavirus is characterized in two ways:

i) Feline enteric coronavirus, or FECV,

ii) Feline infectious peritonitis virus, or FIPV.[5]

Fig. Feline Enteric coronavirus

i] Feline enteric:

Feline enteric coronavirus is usually mild and has few symptoms, if any. FECV has the very real possibility of converting to FIPV, which is highly dangerous and usually deadly.[5]

ii] Feline infectious peritonitis (FIP):

It is a fatal, immune-mediated disease produced as a result of infection of macrophages by mutant feline coronavirus strains (FIPVs). Type II FECVs are viruses that arise as a result of recombinations between type I FECV and canine coronavirus (CCV) FIP occurs most frequently in cats younger than 3 years of age from multiple-cat homes (shelters and breeding catteries) [4]

B) Symptoms of feline coronovirus:

Excessive diarrhea [5]

Fatigue and weakness [5]

Shortness of breath [5]

Sudden unexplained loss of weight [5]

Decreased appetite [5]

C) Identification test for feline coronovirus:

Feline coronavirus can be easily detected with a blood test. Blood testing will determine if a cat's immune system has developed antibodies to the coronavirus and if so, will produce a positive result. What is unfortunate about feline coronavirus is that a blood test does not have the ability to distinguish between FECV and FIP. Only a firm grasp of the symptoms can determine whether or not FECV has mutated into FIP.[5]

D) Treatment for Feline Coronavirus

Unfortunately, there is currently no method of treatment for either strain of the feline coronavirus.[5]

2) Canine Coronavirus classification:

Realm- Riboviria [7]

Phylum- Incertae sedis [7]

Order- Nidovirales [7]

Family- Coronaviridae [7]

Genus- Alphacoronavirus [7]

Subgenus- Tegacovirus [7]

Species- Alphacoronavirus 1 [7]

Virus- Canine coronavirus [7]

A] General Introduction of Canine Coronavirus:

Canine coronavirus (CCoV) is a relatively new intestinal disease in dogs. It was first identified in England in 1971, but it has since spread all around the world. [8] Coronaviruses are found in many different animals including pigs, cows, cats, and humans, as well as dogs. They are an RNA virus, so named because of the corona like halo that appears under a microscope. Viruses can only affect one species, but new strains do develop quickly and may occasionally jump species to form a new disease. CCoV is believed to have come originally from pigs, while another, more recent, canine respiratory coronavirus (CRCoV) may have jumped from cows. Typically, CCoV causes enteritis, inflammation of the small intestine. It is rarely symptomatic in adult dogs, but puppies have diarrhea and sometimes other symptoms as well. It affects weak puppies most commonly. In puppies under three months of age, it can be fatal, but usually because it is combined with another infection. The virus invades the upper intestinal tract within 2 to 3 days and continues to be passed in the feces for 9 days, and sometimes longer. The disease is highly contagious and spreads easily through the feces of infected animals; many dogs can be carriers without actually showing symptoms. Adult dogs that have been exposed develop antibodies to the disease. Puppies can be vaccinated at 6 and 9 weeks of age and should be protected against most forms for life. The respiratory version, CRCoV, is a separate virus that is not responsive to the same antibodies or vaccination. Coronavirus is an infectious disease found in many animals. Typically, coronavirus causes an intestinal infection in dogs. Veterinarians call this canine coronavirus infection. Symptoms are usually only apparent in puppies and dogs with a weakened immune system and the disease is rarely fatal.[8]

B) Symptoms of Canine Coronavirus:

i) Diarrhea [8]

ii) Vomiting [8]

iii) Anorexia [8]

iv) Nausea [10]

v) Lack of appetite [10]

vi) Fever [10]

vii) Cough [10]

viii) sneezing [10]

ix) other respiratory symptom [10]

Fig. Canine coronavirus

[C] Treatment for Canine coronavirus:

Treatment of Canine Coronavirus Infection in Dogs Dehydration is the most common problem with puppies that have CCoV. The puppy should be encouraged to drink independently if possible. Pedialyte can be a good fluid to hydrate puppies. If the puppy will not or cannot drink, fluids and electrolytes will need to be given intravenously. Various medications may be prescribed based on the symptoms. Metoclopramide can relax the intestine, and famotidine or another acid-blocker can help to coat the intestinal walls and protect them against inflammation. With puppies that are also vomiting, anti-emetics may be given. Antibiotics are commonly prescribed to control any concurrent infection which could present a bigger problem with a weakened immune system. Some puppies have hookworm at the same time and need treatment for this as well. A heating pad may be helpful to maintain the proper temperature for young puppies. CCoV is also treated supportively. Antibiotics are given to prevent bacterial infection. Dogs who develop pneumonia along with the virus could need oxygen, but this is rare.[10]

D] Causes of Canine Coronavirus:

Infection in Dogs Coronavirus is spread through contact with other infected animals. Many factors can make it more likely to catch a serious infection.

Staying in a kennel A crowded dog show Any condition of overcrowding Dog with a weakened immune system Puppies Combination with another infection [10]

E) Pathology of Canine Coronavirus:

Coronavirus is spread through contact with other infected animals. Many factors can make it more likely to catch a serious infection. Staying in a kennel A crowded dog show Any condition of overcrowding Dog with a weakened immune system Puppies Combination with another infection [8]

3) Transmissible gastroenteritis classification

Realm- Riboviria [9]

Phylum- incertae sedis [9]

Order- Nidovirales [9]

Family- Coronaviridae [9]

Genus- Alphacoronavirus [9]

Subgenus- Tegacovirus [9]

Species- Alphacoronavirus 1 [9]

Virus- Transmissible gastroenteritis coronavirus [9]

A] General Introduction of Transmissible gastroenteritis coronavirus:

Transmissible gastroenteritis coronavirus (TGEV) is A virus subspecies belonging to the family Coronaviridae, genus Alphacoronavirus, species Alphacoronavirus 1.[9]

The morphology of TGEV was mostly determined by electron microscopy techniques. The viruses are mainly circular in shape with a diameter ranging from 100 to 150 nm including the surface projections. The projections were mainly petal-shaped attached by a very narrow stalk. The projections seemed to be very easily detached from the virus and were only found on select areas.[9]

[B] Pathology of Transmissible gastroenteritis coronavirus:

TGEV infects pigs. In piglets less than 1 week old, the mortality rate is close to 100%. The pathology of TGEV is similar to that of other coronaviruses. Once the virus infects the host, it multiplies in the cell lining of the small intestine resulting in the loss of absorptive cells that in turn leads to shortening of villi. The infected swine then have reduced capability for digesting food and die from dehydration.[9]

4] Porcine epidermic diarrhoea coronavirus classification:

Realm- Riboviria

Phylum-Incertae sedis

Order- Nidovirales

Family- Coronaviridae

Genus- Alphacoronavirus

Sub- Genus- Pedacovirus

Virus- Porcine epidermic diarrhoea coronavirus[11]

[A] General Introduction of Porcine epidermic diarrhoea coronavirus:

Porcine epidemic diarrhea virus (PED virus or PEDV) is a coronavirus that infects the cells lining the small intestine of a pig, causing porcine epidemic diarrhoea, a condition of severe diarrhea and dehydration. Older hogs mostly get sick and lose weight after being infected, whereas newborn piglets usually die within five days of contracting the virus. PEDV cannot be transmitted to humans, nor contaminate the human food supply.

It was first discovered in Europe, but has become increasingly problematic in Asian countries, such as Korea, China, Japan, the Philippines, and Thailand. It has also spread to North America: it was discovered in the United States on May 5, 2013 in Indiana, and in Canada in the winter of 2014. In January 2014, a new variant strain of PEDV with three deletions, one insertion, and several mutations in S (spike) 1 region was identified in Ohio by the Animal Disease Diagnostic Lab of Ohio Department of Agriculture.

PEDV has a substantial economic burden given that it is highly infectious, resulting in significant morbidity and mortality in piglets. Morbidity and mortality rates were lower for vaccinated herds than for nonvaccinated herds, which suggests the emergence of a new PEDV field strain(s) for which the current vaccine, based on the CV777 strain, was partially protective. Consumers are likely to feel the effects of the viral disease in the form of higher prices for pork products.[11]

Types;

i] PEDv Type-I

ii] PEDv Type-II

i] PEDv Type-I- PEDv Type I only affects growing pigs.

ii] PEDv Type-II- PED Type II affects all ages including sucking pigs and mature sows [12]

B] Treatment of Porcine epidermic diarrhoea coronavirus-

No specific treatment for PEDv is available. Affected pigs should be kept warm, dry, and well hydrated with oral electrolyte supplementation. In very young animals, treatment is usually futile. If secondary bacteria complicate the clinical disease or are likely to, then broad-spectrum antibiotics may be prescribed. If the virus enters the herd for the first time it is important to ensure that all the adult animals become infected at an early stage to allow an early immunity to develop. This can be achieved by exposing sows to the diarrhoea three times, two days apart via the drinking water, this practice is known as ‘feedback’. Mix scour or contaminated material into a bucket of water and use this as the source. The use of feedback technique must be performed under the rules laid down and detailed on the UK Pig Veterinary Society website under “controlled exposure”.[12]

C] Signs and Symptoms of Porcine epidermic diarrhoea coronavirus-

The clinical signs of disease are very age-specific and much more severe in younger animals. In very young piglets there is profuse, watery diarrhoea, without blood or mucus, which is usually yellow-green in colour, often accompanied with vomiting and anorexia which may lead to death in up to 100% of the piglets less than a week old. Pigs over a week of age typically recover but with growth rate losses of circa 10%. When older animals (nursery, grower, finisher, sows, boars) become infected they may go off feed for two to four days, have loose faeces or watery diarrhoea with no blood or mucus and vomit – dehydration is common. A death rate of 1 to 3% in the post-weaned animals is typical.

The incubation period is typically two to four days and the first clinical signs in a herd are seen approximately four days after PEDv enters the herd. When the virus is first introduced on to the farm there is a rapid spread of diarrhoea across all breeding (Type II) and growing pigs (Type I and II) with almost 100% morbidity (pigs affected) within 5 to 10 days, although in outdoor extensively kept pigs this time may be protracted.

There are other diseases that cause very similar clinical signs, such as; coccidiosis, transmissible gastroenteritis (TGE), rotavirus diarrhoea, Clostridium perfringens enterotoxaemia, and E. coli scours. It is now a legal requirement to contact your vet or the Official Veterinarian (OV) at your local APHA in such cases to rule out PED, they will submit samples to the APHA for a diagnosis.[12]

5) Porcine haemagglutinating encephalomyelitis coronavirus classification-

Relam –Riboviria

Phylum- Incertae sedis

Order- Nidovirales

Family- Coronaviridae

Genus – Betacoronavirus

Subgenus- Embecovirus

Species- Betacoronavirus 1[13]

A] General Introduction Of Porcine hemagglutinating encephalomyelitis coronavirus-

The porcine hemagglutinating encephalomyelitis virus (PHEV) is the causative agent of neurological and/or digestive disease in pigs. PHEV was one of the first swine coronaviruses identified and isolated, and the only known neurotropic virus that affects pigs. However, PHEV remains among the least studied of the swine coronaviruses because of its low clinical prevalence reported in the swine industry worldwide. PHEV can infect naïve pigs of any age, but clinical disease is age-dependent. Clinical manifestations, including vomiting and wasting and/or neurological signs, are age-related, and generally reported only in piglets under 4 weeks old. Subclinical circulation of PHEV has been reported nearly worldwide in association with a high seroprevalence in swine herds. Protection from the disease could be provided through lactogenic immunity transferred from PHEV seropositive sows to their offspring in enzootically infected herds. However, PHEV still constitutes a potential threat to herds of high-health gilts, as evidenced by different outbreaks of vomiting and wasting syndrome and encephalomyelitis reported in neonatal pigs born from naïve sows, with mortality rates reaching 100%. In absence of effective vaccine, the best practice for preventing clinical disease in suckling piglets could be ensuring that gilts and sows are PHEV seropositive prior to farrowing.[13]

Coronaviruses (CoVs) belong to the Nidovirales order, which includes the Coronaviridae, Arteriviridae, and Roniviridae families. The subfamily Cornavirinae is further divided into four genera: Alphacoronavirus, Betacoronavirus, Gammacoronavirus, and Deltacoronavirus. Coronaviruses are enveloped and pleomorphic positive-sense RNA viruses, characterized by club-like spikes projected from their surface, a large RNA genome, and a unique replication strategy . The overall diameter of CoVs can range from 60 to 160 nm as demonstrated by negative-staining electron microscopy (EM). The phospholipids and glycolipids incorporated into the virus envelope are derived from the host cell cellular membranes, and therefore the envelope composition is host cell-dependent .Most CoVs have a single layer of club-shaped spikes (S protein) 12–25 nm in length, but PHEV and some other betacoronaviruses have a second, shorter layer of surface spikes, the hemagglutinin-esteras[13]

Fig. Porcine epidermic diarrhoea coronavirus

6] Bovine Coronavirus classification-

Realm – Riboviria

Phylum- Incertae sedis

Order- Nidovirales

Family- Coronaviridae

Genus- Betacoronavirus

Species – Betacoronavirus 1

Virus - Bovine coronavirus[14]

A] General Introduction of bovine coronavirus-

Bovine coronavirus (BCV or BCoV) is as a member virus of the Coronaviridae family which are enveloped, single-stranded, positive-sense RNA viruses with a club-shaped surface. Infection causes calf enteritis and contributes to the enzootic pneumonia complex in calves. It can also cause winter dysentery in adult cattle. It can infect both domestic and wild ruminants and has a worldwide distribution. Transmission is horizontal, via oro-fecal or respiratory routes.[14]

B] Signs symptoms of bovine Coronavirus-

Infection normally occurs in calves between the ages of one week and three months. Gastrointestinal signs include profuse diarrhea, dehydration, depression, reduced weight gain and anorexia. Respiratory infection in the calf produces a serous to purulent nasal discharge. Clinical signs may worsen with secondary bacteria infection.

Infection in adults is normally subclinical, the exception being with winter dysentery, which affects housed cattle over the winter months. Clinical signs include profuse diarrhea and a significant drop in milk yield is seen in winter dysentery outbreaks.

A presumptive diagnosis can be made based on the history and clinical signs. Definitive diagnosis of an enteric coronavirus infection is achieved by performing electron microscopy or an ELISA on a faecal or tissue sample. In respiratory disease, diagnosis is confirmed by performing a direct fluorescent antibody test on nasal washes – which identifies the viral antigen. [14]

The haemagglutination inhibition test can be used to establish the strain of coronavirus.

C]Treatment of Bovine Coronavirus:

Animals should be treated symptomatically. The disease can be controlled by vaccinating the dam with a live vaccine (ATCvet code QI02) whilst she is pregnant as this provides antibodies to the virus in the colostrum. Additional management factors such as ensuring adequate colostrum intake in newborn calves, using appropriate hygiene methods and ventilation of housing reduce disease incidence.[14]

Fig. Bovine Coronavirus

7] Severe acute respiratory coronavirus classification-

Relam- Riboviria

Phylum-Incertae sedis

Order-Nidovirales

Family- Coronaviridae

Genus- Betacoronavirus

Subgenus- Sarbecovirus

Virus-Severe acute respiratory coronavirus

A] General Introduction of severe acute respiratory coronavirus:

SARS, or severe acute respiratory syndrome, is the disease caused by SARS coronavirus. It causes an often severe illness marked initially by systemic symptoms of muscle pain, headache, and fever, followed in 2–14 days by the onset of respiratory symptoms, mainly cough, dyspnea, and pneumonia. Another common finding in SARS patients is a decrease in the number of lymphocytes circulating in the blood.

In the SARS outbreak of 2003, about 9% of patients with confirmed SARS infection died.The mortality rate was much higher for those over 60 years old, with mortality rates approaching 50% for this subset of patients.

B] Signs and symptoms of severe acute respiratory coronavirus:

Initial symptoms are flu-like and may include fever, muscle pain, lethargy symptoms, cough, sore throat, and other nonspecific symptoms. The only symptom common to all patients appears to be a fever above 38 °C (100 °F). SARS may eventually lead to shortness of breath and pneumonia; either direct viral pneumonia or secondary bacterial pneumonia.

The average incubation period for SARS is 4–6 days, although rarely it could be as short as 1 day or as long as 14 days.

C] Cause of Severe acute respiratory coronavirus:

The primary route of transmission for SARS is contact of the mucous membranes with respiratory droplets or fomites. Whilst diarrhea is common in people with SARS, the fecal-oral route does not appear to be a common mode of transmission. The basic reproduction number of SARS, R₀, ranges from 2 to 4 depending on different analyses. Control measures introduced in April 2003 reduced this down to 0.4.

D] Diagnosis Of Severe acute respiratory coronavirus:

A chest X-ray showing increased opacity in both lungs, indicative of pneumonia, in a patient with SARS

SARS may be suspected in a patient who has:

· Any of the symptoms, including a fever of 38 °C (100 °F) or higher, and

· Either a history of:

· Contact (sexual or casual) with someone with a diagnosis of SARS within the last 10 days or

· Travel to any of the regions identified by the World Health Organization (WHO) as areas with recent local transmission of SARS.

For a case to be considered probable, a chest X-ray must be positive for atypical pneumonia or respiratory distress syndrome.

The WHO has added the category of "laboratory confirmed SARS" for patients who would otherwise be considered "probable" but who have not yet had a positive chest X-ray changes, but have tested positive for SARS based on one of the approved tests (ELISA, immunofluorescence or PCR).

The appearance of SARS in chest X-rays is not always uniform but generally appears as an abnormality with patchy infiltrates.

E] Prevention Of Severe acute respiratory coronavirus:

There is no vaccine for SARS. Clinical isolation and quarantine remain the most effective means to prevent the spread of SARS. Other preventive measures include:

· Hand-washing

· Disinfection of surfaces for fomites

· Wearing a surgical mask

· Avoiding contact with bodily fluids

· Washing the personal items of someone with SARS in hot, soapy water (eating utensils, dishes, bedding, etc.)

· Keeping children with symptoms home from school

· Simple hygiene measures

· Isolating oneself as much as possible to minimize the chances of transmission of the virus

Many public health interventions were made to try to control the spread of the disease, which is mainly spread through respiratory droplets in the air. These interventions included earlier detection of the disease; isolation of people who are infected; droplet and contact precautions; and the use of personal protective equipment (PPE), including masks and isolation gowns. A screening process was also put in place at airports to monitor air travel to and from affected countries. Although no cases have been identified since 2004, the CDC is still working to make federal and local rapid response guidelines and recommendations in the event of a reappearance of the virus.

SARS is most infectious in severely ill patients, which usually occurs during the second week of illness. This delayed infectious period meant that quarantine was highly effective; people who were isolated before day five of their illness rarely transmitted the disease to others.

F] Treatment of severe acute coronavirus:

Antibiotics are ineffective, as SARS is a viral disease. Treatment of SARS is mainly supportive with antipyretics, supplemental oxygen and mechanical ventilation as needed. Antiviral medications are used as well as high doses of steroids to reduce swelling in the lungs.

People with SARS must be isolated, preferably in negative pressure rooms, with complete barrier nursing precautions taken for any necessary contact with these patients, to limit the chances of medical personnel getting infected with SARS.

Some of the more serious damage caused by SARS may be due to the body's own immune system reacting in what is known as cytokine storm.

As of 2020, there is no cure or protective vaccine for SARS that has been shown to be both safe and effective in humans. According to research papers published in 2005 and 2006, the identification and development of novel vaccines and medicines to treat SARS is a priority for governments and public health agencies around the world. It is reported in early 2004, an early clinical trial on volunteers is planned.

+ve acute syndrome

G] Identification of SAR coronavirus:

In late February 2003, Italian doctor Carlo Urbani was called into The French Hospital of Hanoi to look at Johnny Chen, an American businessman who had fallen ill with what doctors thought was a bad case of influenza. Urbani realized that Chen's ailment was probably a new and highly contagious disease. He immediately notified the WHO. He also persuaded the Vietnamese Health Ministry to begin isolating patients and screening travelers, thus slowing the early pace of the epidemic. He subsequently contracted the disease himself, and died in March 2003.

The CDC and Canada's National Microbiology Laboratory identified the SARS genome in April 2003. Scientists at Erasmus University in Rotterdam, the Netherlands demonstrated that the SARS coronavirus fulfilled Koch's postulates thereby confirming it as the causative agent. In the experiments, macaques infected with the virus developed the same symptoms as human SARS victims.In late May 2003, studies were conducted using samples of wild animals sold as food in the local market in Guangdong, China. The results found that the SARS coronavirus could be isolated from masked palm civets (Paguma sp.), even if the animals did not show clinical signs of the virus. The preliminary conclusion was the SARS virus crossed the xenographic barrier from asian palm civet to humans, and more than 10,000 masked palm civets were killed in Guangdong Province. The virus was also later found in raccoon dogs (Nyctereuteus sp.), ferret badgers (Melogale spp.), and domestic cats. In 2005, two studies identified a number of SARS-like coronaviruses in Chinese bats.

Phylogenetic analysis of these viruses indicated a high probability that SARS coronavirus originated in bats and spread to humans either directly or through animals held in Chinese markets. The bats did not show any visible signs of disease, but are the likely natural reservoirs of SARS-like coronaviruses. In late 2006, scientists from the Chinese Centre for Disease Control and Prevention of Hong Kong University and the Guangzhou Centre for Disease Control and Prevention established a genetic link between the SARS coronavirus appearing in civets and humans, bearing out claims that the disease had jumped across species.

In December 2017, "after years of searching across China, where the disease first emerged, researchers reported that they had found a remote cave in Yunnan province, which is home to horseshoe bats that carry a strain of a particular virus known as a coronavirus. This strain has all the genetic building blocks of the type that triggered the global outbreak of SARS in 2002." The research was performed by Shi Zheng-Li, Cui Jie and coworkers at the Wuhan Institute of Virology, China, and published in PLOS Pathogens. The authors are quoted as stating that "another deadly outbreak of SARS could emerge at any time. As they point out, the cave where they discovered their strain is only a kilometre from the nearest village.[15]

8] Infected bronchitis coronavirus classification:

Relam- Riboviria

Phylum- Incertae Sedis

Order- Nidovirales

Family- Coronaviridae

Genus- Gammacoronavirus

Virus- Avian infectious bronchitis virus [16]

A] General Introduction of Infected bronchitis coronavirus:

Avian infectious bronchitis virus (IBV) is a coronavirus which infects chickens, causing the associated disease, infectious bronchitis (IB). It is a highly infectious avian pathogen which affects the respiratory tract, gut, kidney and reproductive systems of chickens.

There is also evidence that IBV can infect other avian species. IBV affects the performance of both meat producing and egg producing chickens and is responsible for substantial economic loss within the poultry industry.

IBV is a coronavirus, in the genus Gammacoronavirus,or group 3, with a non-segmented, positive-sense single-stranded RNA genome.[16]

B] Pathology of infectious bronchitis virus:

Respiratory system:

When inhaled, virus will attach to glycoprotein receptors containing sialic acid on ciliated epithelial cells of the respiratory epithelium. The respiratory replication will result in loss of ciliary activity, mucus accumulation, necrosis and desquamation, causing respiratory distress, râles and asphyxia. Local virus replication will result in viremia, spreading the infection into other tissues and organs. Other respiratory diseases of chickens (Mycoplasma gallisepticum, avian infectious laryngotracheitis (Gallid alphaherpesvirus 1), Newcastle disease (avian paramyxovirus 1), Avian metapneumovirus infection may be confused clinically to infectious bronchitis.

Kidney:

Through viremia, some nephrotropic strains (most of high virulence) could infect the kidney epithelium in tubules and nephron, causing kidney failure. At gross examination, kidneys may appear swollen and pale in color and with urates in ureters.

Reproductive system:

In hens, the viremic IBV will also reach the oviduct, causing lesions in the magnum (the egg-white gland) and in the uterus (the egg-shell gland), leading to a sharp decline of egg production, shell-less, fragile or roughened shells eggs (uterus lesion) with watery whites (magnum lesion). Infection of chickens at puberty, during the oviduct development, will impede oviduct formation and destroy future laying capacity, resulting in "false layers". However, other diseases affecting layer chickens could lead to that condition.

C] Vaccines of infectious bronchitis virus:

There are both attenuated vaccines and inactivated vaccines available. Their effectiveness is diminished by poor cross-protection. The nature of the protective immune response to IBV is poorly understood, but the surface spike protein, the amino-terminal S1 half, is sufficient to induce good protective immunity. Experimental vector IB vaccines and genetically manipulated IBVs-with heterologous spike protein genes-have produced promising results, including in the context of in ovo vaccination.[16]

Fig.Infected bronchitis

9] Turkey coronavirus classification:

Relam- Riboviria

Phylum- Incertae Sedis

Order- Nidovirales

Family- Coronaviridae

Virus- Turkey coronavirus

A] General Introduction of Turkey coronavirus:

Turkey coronaviruses are members of the family

has been noted in North America, Europe and Brazil. Coronaviridae, in the Gammacoronavirus group,^[1] that infect turkeys, especially poults, leading to gastrointestinal disease. Viruses include turkey enteritis virus and bluecomb disease virus. Transmission is horizontal via the faeces, and can be direct or indirectly spread by fomites.

Disease:

Avian infectious bronchitis is a closely related disease.

B] Clinical signs and diagnosis:

Gastrointestinal disease appears as diarrhoea, anorexia and lethargy. Most of the birds in a group are usually affected and their overall appearance is of darkened skin and ruffled feathers. In the US, a turkey coronavirus is one of the pathogens responsible for the Poult Enteritis and Mortality Syndrome (PEMS) in birds under the age of one month. Recovered birds are immune for life but may become carriers.

Necropsy, histology, indirect immunofluorescence, immunoperoxidase staining, ELISA and PCR can all be used for diagnosis.

C] Treatment and control:

Supportive therapy can be given, including heat lamps, antibiotics, and milk replacer.

It is recommended that turkey farms be depopulated in the event of an outbreak.[17]

REFERENCE:

1. J.S.M. Peiris, in Medical Microbiology (Eighteenth Edition), 2012 Kiddle Encyclopedia.

2. Virus pathogen virus de Groot, R.J., Cowley, J.A, Enjuanes, L., Faaberg, K.S., Perlman, S., Rottier, P.J.M., Snijder, E.J., Ziebuhr, J. and Gorbalenya, A.E.

3. Kiddle Encyclopedia This page was last modified on 1 February 2020, at 13:30

4. Review, J Vet Intern Med 2001;15:438–444 A Review of Coronavirus Infection in the Central Nervous System of Cats and Mice.

5. https://www.vetinfo.com/feline-coronavirus-infection.html

6. https://en.wikipedia.org/wiki/Feline_coronavirus

7. https://en.wikipedia.org/wiki/Canine_coronavirus

8. https://wagwalking.com/condition/canine-coronavirus-infection

9. https://en.wikipedia.org/wiki/Transmissible_gastroenteritis_virus

10. https://wagwalking.com/condition/canine-coronavirus-infection

11. https://en.wikipedia.org/wiki/Porcine_epidemic_diarrhea_virus

12. https://thepigsite.com/disease-guide/porcine-epidemic-diarrhoea-ped-scour

13. Frontiers in Veterinary Science “Porcine hemagglutinating encephalomyelitis virus: A Review by Juan carlos mora-diaz, Pablo Enrique Pineyro, Elizabeth Houston, Jeffrey Zimmerman and luis Gabriel on 2019 feb27

14. https://en.wikipedia.org/wiki/Bovine_coronavirus

15. https://en.wikipedia.org/wiki/Severe_acute_respiratory_syndrome-related_coronavirus

16. https://en.wikipedia.org/wiki/Avian_infectious_bronchitis_virus

17. https://en.wikipedia.org/wiki/Turkey_coronavirus

Received on 10.02.2020 Modified on 16.03.2020

Asian J. Res. Pharm. Sci. 2020; 10(2):115-123.

DOI: 10.5958/2231-5659.2020.00022.3