Avian Influenza

Commonly known as 'bird flu' Avian Influenza is a highly contagious viral disease affecting the respiratory, digestive and/or nervous system of many species of bird. It is primarily a disease of birds, however humans and other mammals can be afftected on occasion.

Transmission
-AI is not an air-borne infection.
-It is acquired by direct contact or by indirect contact with contaminated material (e.g. faeces of infected birds).
-There is currently a large threat of this in Asia with infected poultry due to low hygiene conditions and close quarters.
-There are many strains of AI viruses which vary in their ability to cause disease (pathogenicity). They are categorized as either highly pathogenic avian influenza viruses (HPAI) or low pathogenic (LPAI). It is thought that LPAI is common amongst European poultry.
-HPAI can spread easily and quickly between birds in poultry populations and cause severe disease, with a high death rate. In rare cases, some HPAI strains have lead to severe disease and deaths in people where infection has resulted from close contact with infected birds.
-The highly pathogenic H5N1 strain of the virus became known in South East Asia in 2004, and has led to the destruction of millions of birds. A series of H5N1 outbreaks in domestic and wild birds have occurred across Europe, including Great Britain, but with early detection and effective control these were eradicated quickly.




The red regions are the areas that have reported poultry deaths due to H5N1, dark red shows sountries that have had human infection with H5N1. It is clear that Asia is most severely affected.

Symptoms in Birds
-oedema (swelling) of the head
-cyanosis (blue discolouration) of the comb and wattles (neck and throat area)
-dullness, a loss of appetite, respiratory distress, diarrhoea and a drop in egg production.

Extra Information
Health experts are concerned that the coexistence of human flu viruses and avian flu viruses (especially H5N1) will provide an opportunity for genetic material to be exchanged between species-specific viruses, possibly creating a new virulent influenza strain that is easily transmissible and lethal to humans. The mortality rate for humans with H5N1 is 60%.

Although millions of birds have become infected with the virus since its discovery, 359 humans have died from the H5N1 in twelve countries.

This photo shows the difference in the colour of comb of the infected chicken (left) and healthy chicken (right).





Bovine Spongiform encephalopathy

Bovine spongiform encephalopathy (BSE), commonly known as mad cow disease, is a fatal neurodegenerative disease (encephalopathy) in cattle that causes a spongy degeneration in the brain and spinal cord. BSE has a long incubation period, about 30 months to 8 years, usually affecting adult cattle at a peak age onset of four to five years, all breeds being equally susceptible. In the United Kingdom, the country worst affected, more than 180,000 cattle have been infected and 4.4 million slaughtered during the eradication program.

The disease can be easily transmitted to humans by contamination of food with the brain, spinal cord or digective tract of infected organs. However, the infective agent is present in almost all bodily tissues of infected animals (blood included), which is why transmission is so likely through consumption of meat products.

The disease was spread as a result of cattle (normally herbivores) being fed on the remains of other bovines that were infected (e.g. in meat and bone meal).  The accumulation of misfolded proteins (BSE prions) in the brain occured, causing symptoms and eventual death.The epidemic was probably accelerated by the recycling of infected bovine tissues prior to the recognition of BSE. The origin of the disease itself remains unknown. The infectious agent is distinctive for the high temperatures at which it remains viable.

The first confirmed animal to fall ill with the disease occurred in 1986 in the United Kingdom, and lab tests the following year indicated the presence of BSE; by November 1987, the British Ministry of Agriculture accepted it had a new disease on its hands.Subsequently, 165 people (until October 2009) acquired and died of a disease with similar neurological symptoms subsequently called (new) variant Creutzfeldt-Jakob disease.

Symptoms in cattle:
-Change in attitude/behaviour
-Inability to coordinate simple movements e.g. standing and walking
-Weight loss but not appetite loss
-Limited milk production

Schmallenberg Virus

In November 2011 a new virus was identified which had been causing problems in Germany and the Netherlands since August. This was named ‘Schmallenberg virus’ (SBV) after the German town where the virus was first identified.

Between August and October 2011, outbreaks of disease in adult cattle that included mild to moderate fever, reduced milk yield, loss of appetite, loss of body condition and diarrhoea were reported in both the Netherlands and Germany. Testing for common causes proved negative.From December 2011, abortion and stillbirths associated with foetal abnormalities, affecting mainly sheep but also cattle and goats, were identified in the Netherlands, Germany and Belgium.  At the begining of 2012 there were suspected cases in thr South and East parts of England. Deformed lamb were tested and the viral infection was confirmed to be the cause. Further cases occured in Southern and Central England later.

As yet, the disease has remained soley European with outbreaks in: Germany, Belgium, England, the Netherlands, Denmark, Spain and Italy. So far the disease has only affected goats, sheep and cattle. The disease is highly unlikely to be zoonotic (affecting humans), as so far no human cases have been detected and the viral strains clostest to the SBV all only affect animals.

Transmission

It is suspected that the disease is transmitted by biting insect vectors, such as midges and mosquitos but the exact mechanism of transmission is still unknown due to the recent nature of outbreaks. It is likely that initial introduction of the virus to the UK resulted from wind-blown insect vectors originating in Europe.


Symptoms


-In adult animals: diarrhoea, fever, a reduction in milk yield, with a full and rapid recovery over several days. The infection tends to remain with the herd for 3-2 weeks.

-In Newborns and Foetuses: The second presentation of the disease is associated with abnormalities in animals born alive or dead at term or aborted following infection of the dam, affecting mainly sheep but also cattle and goats. Malformations observed to date include bent limbs and fixed joints (arthrogryposis), twisted neck or spine, a domed appearance to the skull, short lower jaw and brain deformities (spaces filled with fluid in cerebral hemispheres, abnormally small parts such as cerebellum and brainstem) and marked damage to the spinal cord.

Diagnosis/ Post mortem techniques

Histopathological: Microscopic examination of tissues in order to study disease manifestations.
Serological: The study of blood serum and other bodily fluids in order to test for disease.
Virological: The study of the infecting virus.
- Carcasses of abnormal lamb/calves should be sent to the VLA with a blood clot from the dam; this allows an indirect test for antibodies to be conducted.

Treatment

There is no treatment or vaccine currently available for this disease. As this is a new disease further work is needed to determine what control measures may be appropriate. 

Recent News:

A ram in Orkney recently tested positive for SBV after being moved there. The virus is reportedly moving North across britain,and it is vital that farmers maintain good biosecurity to prevent this relatively problematic virus from spreading further. Having isolated the virus, vaccinations are currently being developed in order to trigger the body to produce virus neautralizing antibodies, and the aim is to have a vaccine by the end of 2012.

ANTHRAX

Anthrax is an infectious disease due to a type of bacteria called Bacillus anthracis. Infection in humans most often involves the skin, gastrointestinal tract, or lungs.

Anthrax commonly affects hoofed animals such as sheep, cattle, and goats, but humans who come into contact with infected animals can be infected with anthrax, too. In the past, the people who were most at risk for anthrax included farm workers, veterinarians, and tannery and wool workers. In recent years, anthrax has received a great deal of attention as it has become clear that the infection can also be spread by a bioterrorist attack or by biological warfare. Anthrax does not spread from person to person. It was a German physician and scientist, Dr. Robert Koch, who proved that the anthrax bacterium was the cause of a disease that affected farm animals in his community. Under the microscope, the bacteria look like large rods. However, in the soil, anthrax organisms exist in a dormant form called spores. These spores are very hardy and difficult to destroy. The spores have been known to survive in the soil for as long as 48 years. The anthrax bacillus prefers alkaline soils and alternating periods of flooding and drought.

Anthrax can infect humans in three ways:

1. The most common is infection through the skin, which causes an ugly sore that usually goes away without treatment.
2. Humans and animals can ingest anthrax from carcasses of dead animals that have been contaminated with anthrax. Ingestion of anthrax can cause serious, sometimes fatal disease.
3.The most deadly form is inhalation anthrax. If the spores of anthrax are inhaled, they migrate to lymph glands in the chest where they proliferate, spread, and produce toxins that often cause death.

Epidemiology:
-In herbivores, anthrax commonly presents as an acute septicemia with a high fatality rate, often accompanied by hemorrhagic lymphadenitis.

-Underdiagnosis and unreliable reporting make it difficult to estimate the true incidence of anthrax worldwide. However, anthrax has been reported from nearly every continent and is most common in agricultural regions with neutral or alkaline, calcareous soils. In these regions, anthrax periodically emerges as epizootics among susceptible domestic and wild animals. These epizootics are usually associated with drought, flooding, or soil disturbance, and many years may pass between outbreaks. During interepidemic periods, sporadic cases may help maintain soil contamination.

Pathogenesis:

-B anthracis spores have a high affinity for macrophages. After wound inoculation, ingestion, or inhalation, spores infect macrophages, germinate, and proliferate. In cutaneous and GI infection, proliferation can occur at the site of infection and the lymph nodes draining the site of infection. Lethal toxin and edema toxin are produced by B anthracis and respectively cause local necrosis and extensive edema, which is a frequent characteristic of the disease. As the bacteria multiply in the lymph nodes, toxemia progresses and bacteremia may ensue. With the increase in toxin production, the potential for disseminated tissue destruction and organ failure increases. After vegetative bacilli are discharged from an animal following death (by carcass bloating, scavengers, or postmortem examination), the oxygen content of air induces sporulation. Spores are relatively resistant to extremes of temperature, chemical disinfection, and dessication. Necropsy is discouraged because of the potential for vegetative cells to be exposed to air, resulting in large numbers of spores being produced. Because of the rapid pH change following death and decomposition, vegetative cells in an unopened carcass quickly die without sporulating

Symptoms in infected cattle

- Among cattle and sheep, the period of illness is often so short that the affected animals may be found dead without signs of illness having been noticed. Nevertheless, anthrax is not always rapidly fatal to cattle and sheep, and an affected animal may be ill for several days before death occurs. Any of the following symptoms may be observed: high temperature, shivering and twitching, harsh dry coat, fits, bright staring eyes, colicky pains, dejection, refusal of food, and marked decrease or complete loss of milk. Occasionally a small trickle of blood from the nostrils is visible and there may also be blood in the dung.

Treatment

-Treatment is seldom possible for animals infected with anthrax because of the rapid and fatal course of the disease once symptoms become apparent. However, if time permits, antibiotic drugs may be used with good effect. If animals are likely to be continually exposed to infection, for example by grazing over infected pastures, vaccination with anthrax spore vaccine is recommended.

-This vaccine is safe to use and protects the animals for six months or more. Animals remain in a susceptible state, however, for about ten days after vaccination, and should be isolated as far as possible from contact with possible sources of infection during this period.

-When the circumstances appear to warrant treatment with antibiotics or vaccine, a veterinary surgeon should be consulted.

Lambing

This lamb was born with joint abnormalities. Initially when born it could walk normally but after a few hours it's joint function deteriorated. We took him away from his mother to feed him by hand and banadaged his joints in the correct position, having castrated him and docked his tail. After a week the skin had become sore and irritated, so we disinfected it with iodine before redressing the front legs. Above, I am seen holding the lamb after redressing him.

Basics of Bluetongue

About The Disease
Bluetongue is a non-contagious viral disease which is transmitted by vector, in this case tiny midges, most commonly found in late summer and autumn. Bluetongue is a disease of animals affecting all ruminants, including sheep, cattle, deer, goats and camelids (camels, llamas, alpacas, guanaco and vicuña). It does not affect horses or pigs. Due to the vector transmission any infected animal must be slaughtered immediately, but culling of the heard is an ineffective method of disease control as bluetongue non-contagious.

Symptoms

-Drooling

-Swelling of the head and neck
-Conjunctivitis  
-Swelling of the mouth
-Swollen teats
-Tiredness

The Virus (BTV)

Bluetongue virus causes serious disease in a lot of livestock. Partly due to this BTV has been in the forefront of molecular studies for last three decades and now represents one of the best understood viruses at the molecular and structural levels. BTV, like the other members of the family is a complex non-enveloped virus with seven structural proteins and a RNA genome consisting of 10 double-stranded (ds) RNA segments of different sizes.

Treatment and Prevention

There is no efficient treatment. Prevention is effected via quarantine, inoculation with live modified virus vaccine and control of the midge vector, including inspection of aircraft.
However, simple husbandry changes and practical midge control measures may help break the livestock infection cycle. Housing livestock during times of maximum midge activity (from dusk to dawn) may lead to significantly reduced biting rates. Similarly, protecting livestock shelters with fine mesh netting or coarser material impregnated with insecticide will reduce contact with the midges. The Culicoides midges that carry the virus usually breed on animal dung and moist soils, either bare or covered in short grass. Identifying breeding grounds and breaking the breeding cycle will significantly reduce the local midge population. Turning off taps, mending leaks and filling in or draining damp areas will also help dry up breeding sites.

Tail Docking

In 1991, the UK government amended the Veterinary Surgeons Act, thereby prohibiting the docking of dog's tails by lay persons. Since then, only qualified registered veterinary surgeons are, by law, allowed to dock. The current legal status of the tail docking of dogs is that tail docking is restricted and illegal (since the Animal Welfare Act of 2007), with the exception of some breeds of working dogs.

In England the following can be docked:

1.      Hunt point retrieve breeds of any type or combination of types.

2.      Spaniels of any type or combination of types.

 3.      Terriers of any type or combination of types.

The dog will have to be less than 5 days old and the veterinary surgeon will have to certify that he or she has seen specified evidence that the dog is likely to work in specified areas. (For example- a current shotgun or firearm certificate issued to the owner of the dog). Puppies being docked must be micro-chipped, either at the time of docking or when the vet considers they are old enough. The vet must sign a declaration that the requirements of the regulations have been satisfied i.e. that he has been given the necessary declaration by the owner or person representing the owner and has seen the evidence required.

Arguments for the ban

-Prior to the 1991 law, amateurs were doing the job badly and inflicting unnecessary pain and injury to the young dogs.

-Docking was being performed for cosmetic purposes as oppose to justified medical or work-related reasons.

-The procedure can be incredibly painful and this pain can result in trauma for the dogs.

It is now illegal for docked dogs to be shown in open/championship dog shows, because since April 2011 docking is against the breed standard.

Arguments against the ban

-Some people believe that the damage caused to the tails of working dogs which are not docked at a young age, is greater than the docking itself would have been. For example, if a working dog injures its tail during a hunt resulting in the need for amputation, this amputation at an older age is likely to be far more painful and expensive than an early tail dock would have been.

-The tail of a dog is not essential for it to function in life.

(Information from: CBD, wiki, Kennel Club, DEFRA and the BVA)