VetPro

Posted by: **jenvetnurse** on Sat Aug 29, 2009 5:20 am

jenvetnurse writes: WITH THANKS TO:

Maggie Fisher BVetMed MRCVS

Early in 1995, the kennel population of more than 100 dogs at the Guide Dogs for the Blind Association's Midlands Regional Centre in Leamington Spa was hit by an unusually severe outbreak of diarrhoea.

The cause turned out to be an infection of the intestine by a commonly-occuring, single celled organism - or protozan known as Giardia. A combined treatment and disinfection strategy was then introduced that brought the infection under control.

Maggie Fisher, a veterinary surgeon with a special interest in parasitology, was called in to help deal with the Giardia outbreak, and in the following paper she describes the infection and how it can be treated and controlled.

The division of Giardia into groups according to species is still somewhat confused; the organisms that infect mammals look very similar but it remains unclear to what extent they form one or a number of species. It is for this reason that, while Giardia infection in some mammals, including dogs, is suspected of being infectious to man (ie: a zoonosis), it has not been conclusively shown that the species in, for example, dogs and man is the same.

The Giardia trophozoite (Figure 1) - which is the active stage of the organism - inhabits the small intestine of the dog. It attaches to the cells of the intestine with its adhesive disc and rapidly divides to produce a whole population of trophozoites.

As they detach they may be swept down the intestine. If intestinal flow is fast then they may appear in the faeces. However, if they have time, they will develop into the inactive, more durable, cyst form of the organism and these will be passed in the faeces. The cyst is more able to survive in the environment than the trophozoite, which is very fragile.

How do Giardia cause disease in dogs?

Like all infectious agents, in order to cause disease Giardia depaends on being able to overcome the dog's defence against infection, either by its virulence or by the number of the organisms becoming established. It has been observed that as few as 10 cycsts can cause disease in humans.

Different anaimals may respond to infection in different ways, which may be due to different strains of the sam Giardia population, with varying levels of pathogenicity. Another explanation for observed differences in the host response to infection is that protective immunity with age and/or exposure. This may be temporarily lost if the animal is stressed or immunosuppressed, for example with corticosteroid treatment.

What is the source of infection for dogs?

The original source of an outbreak may be cysts in contaminated water or the environment. In addition, infected dogs which may be either carriers (ie: show no clinical signs but continue to harbour infection and pass cysts into the environment) or dogs that have diarrhoea associated with infection may act as the source.

Surveys have shown that about 14% of the adult dog population and over 30% of dogs under one year of age were infected. Once passed, the cysts can survive in cold water for several months.
The cysts are infective as soon as they are passed, unlike other parasites where a lag period is necessary before the organism is infective.

The most common route of infection is faeco-oral. For example, dogs may accidentaly eat cysts as they lick around theenvironment or lick other dogs' coats (particularly if the other dog has diarrhoea). Another major source of infection in human cases is drinking contaminated water. Once eaten, the cyst breaks open in the animals' intestine and releases two new trophozoites to initiate infection. If a dog is left in a dirty environment it may act as its own source of further infectionas it eats cysts passed in its own faeces.

What are the clinical signs associated with infection?

The trophozoites divide to produce a large population, then they begin to interfere with the absorption of food, so faeces from affected animals are typically light coloured, greasy and soft. These signs, together with the beginning of cyst shedding, begin about ten weeks post-infection.

There may be additional signs of large intestinal irritation, such as straining and mucus in the faeces, even though the Giardia do not colonise the large intestine. Usually the blood picture of affected animals is normal, though occasionally there is a slight increase in the number of eosinophils (one of several types of white blood cells) and mild anaemia. Without treatment, the condition may continue, either chronically or intermittently, for weeks or months.

How can infection be diagnosed?

Diagnosis is based on demonstration of the infection and the elimination of other possible causes of diarrhoea (eg: Salmonella or Campylobacter), Giardia cysts may be observed directly in faecal samples or indirectly using an elisa technique. Direct examination of faeces, using zinc sulphate centrifugal flotation.

followed by staining the supernatant with Lugol's iodine, has been found to be upto 70% effective at detecting infection from a single faecal sample. The cyst output is very variable from day to day so the detection rate may be improved by pooling faecal samples collected over three days. Faecal examination is the cheapest method but is time consuming and requires an experienced technician for reliable results.

The elisa technique requires a kit and some method of reading a colour change or production of flourescence. Studies examining the reliability of some immunoflourescent kits have found them to be over 90% accurate, with relatively few false negatives or false postives. However, the tests are costly and probably only wothwhile where there are alarge number of samples to be processed and a technician who is familiar with carrying out elisas.

How can infection be treated?

Infection may be traeted using one of a number of drugs. Unfortunately there is no treatment licenced for the control of giardias in dogs, though fenbendazole (Panacur, Hoechst Animal Health) is licenced for treatment of worms in dogs.

Whatever treatment is chosen, itis very unlikely to eliminate 100% of the infection in all dogs.

Treatments for Giardias in dogs:

Metronidazole Flagyl 25-30 mg/kg bid** 7 days

Furazolidone Neftin 4 mg/kg bid* 10 days

Tinadazole - 44 mg/kg once daily 7 days

Fenbendazole Panacur *** 50 mg/kg once daily 3 days

Albendazole Valbazen 25 mg/kg bid 2 days
bid Twice daily

* Maximum daily dose 200 mg

Posted by: **jenvetadmin** on Mon Jul 27, 2009 4:45 am

In the UK, a soon to be published study of DEA (Dog erythrocyte antigen) 1.1 tests reveals that 60 percent of the dog population is DEA 1.1 positive; and 40 percent is DEA 1.1 negative. However, instead of blood typing and using type-matched blood, veterinary practices are ordering only negative blood for transfusing, unwittingly causing negative blood supplies to run low and underutilising available positive blood supplies.
Currently only 25 percent of orders placed with Pet Blood Bank are for positive units, and with 60 percent of donors coming from the DEA 1.1 positive group, a valuable resource is not being fully utilised by practices.
To encourage practices to make use of supplies of positive red blood cell supplies, Pet Blood Bank is offering a 20 percent discount on positive red blood cells throughout the months of July and August. To further assist practices in establishing a blood typing protocol, a 20 percent discount is also applicable to blood typing kits purchased during this time.
“Blood typing is a simple process, and holding accurate records of blood type can save time in an emergency first time blood transfusion situation, ensuring that dogs are transfused rapidly with the correct blood”, says Jenny Walton BVM&S, MRCVS Veterinary Supervisor PBBuk. “Using DEA 1.1 typing alongside tests such as cross matching for patients requiring transfusions on different occasions allows for individual lifelong transfusion therapy to be planned and carried out as safely and scientifically as possible. Long term, it allows volunteer donation programmes such as PBBuk’s to take all donations offered to them and thus continue to supply growing demand in the most effective way.”
Pet Blood Bank UK is a non profit-making organisation which exists to support the veterinary profession, providing emergency blood supplies to practices across the UK. Blood unit charges are set against the cost of running the service, and invested in ongoing research programmes. Vets are urged to establish good practice where blood typing is concerned in order that they can fully benefit from the service if the need arises. By blood typing canine patients as a matter of course, and ordering the correct blood, practices can help Pet Blood Bank to continue to provide an effective service to animals in need.
For further details, please contact Pet Blood Bank on 01509 232 222, or visit the website www.petbloodbankuk.org.

Posted by: **jenvetadmin** on Sun May 31, 2009 6:28 am

Enough blood was collected to save the lives of up to 32 dogs at a Pet Blood Bank UK (PBBuk) collection session at the University of Nottingham’s School of Veterinary Medicine and Science on Wednesday (May 20).
The blood collection session celebrated the launch of a brand new mobile unit, the first of its kind, donated by specialist pet food manufacturer, Royal Canin. The unit will allow Pet Blood Bank UK to tour the country’s vet schools and reach more donors.
Taking place at the veterinary school, the blood collection session offered third-year university students an opportunity to learn about transfusion medicine and to practice their clinical skills on real life subjects, as they performed the pre-donation checks and tests under the close supervision of Pet Blood Bank UK veterinary advisers.
Vanessa Ashall, Pet Blood Bank UK welfare officer and veterinary surgeon, said: “It is great for students to be able to see these animals. Transfusion medicine is a new science and I certainly wasn’t taught about it as a veterinary student.
Collaboration with veterinary schools is such a positive step, as we are able to educate the vets of the future on the benefits of transfusion medicine and blood typing, whilst giving them some real hands-on experience.”
Veterinary support manager for Royal Canin, Chris Geddes, said: “We are really pleased to be able to assist Pet Blood Bank UK become more mobile and reach more donors. The charity’s work is so important to the emergency and critical care of patients, as shown by the tremendous gratitude of the owners of blood recipients.”
Golden retriever Beau was one such recipient who had received a transfusion last month after suffering a haemorrhage after surgery for gastric dilatation and volvulus. His owners, Janet and David Liggins, attended the event with a fully-recovered Beau and their other golden retriever, Lotti who gave blood.
Mrs Liggins said: “We can’t speak highly enough of all the vets and vet nurses that cared for him – they did a tremendous job looking after Beau, and us! The Pet Blood Bank provided the blood that saved Beau’s life. We are really pleased that Lotti was able to give blood. She was a star – the perfect donor!”
Veterinary practices wanting to encourage their clients to put dogs forward as donors, or which would like to support the work of Pet Blood Bank UK, should visit:
www.petbloodbankuk.org or contact Pet Blood Bank UK on 01509 232 222 or 0844 800 9925 (5p/min).

Posted by: **jenvetnurse** on Thu May 21, 2009 5:06 am

jenvetnurse writes: The patient must already have a serious problem before DIC sets in.

Typical conditions that are associated with DIC include those involving dying internal tissue, widespread inflammation, red blood cell destruction, poor circulation, particulate matter in the bloodstream, or loss of blood vessel integrity.

The sooner DIC is recognized, the more likely the chance of a positive outcome.

At first, there are no signs at all, just subtle blood test changes. It is important to for the medical staff to watch for these lab changes in patients known to have diseases associated with DIC.

There are several factors that go into the diagnosis of DIC and a patient need not have them all:

Low platelet count:

Platelets are the white blood cells that are involved in clotting blood. In DIC, they are depleted.

Evidence of inappropriate bleeding:

This could be bruising in the skin, excessive bleeding after a blood sample is taken, or spontaneous bleeding from the gums or from any orifice.

Increases in Blood Clotting Times:

Tests called the PT and PTT are run to assess how long different blood clotting proteins take to produce a blood clot. These times are compared to standardized “normal” times. Increased clotting times indicate a tendency to bleed inappropriately. Clotting times well below the normal range can indicate a hypercoagulable state.

Presence of Fibrin Degradation Products:
(sometimes called “fibrin split products”)
Fibrin is the material that clots are made of. When antithrombin and other biochemicals remove clots, fibrin fragments become detectable.

These are fibrin degradation products. A fibrin degradation product of note is called the “D-Dimer.” It is notable because there are in-hospital test kits that can be used to detect it.

The presence of D-dimer definitely indicates that a clot has been made and broken down (though, there are many reasons for such a thing to have occurred other than DIC).

The absence of D-Dimer rules out DIC with 95% confidence.

Reduced Fibrinogen blood levels:

Fibrinogen is a fibrin precursor and its absence suggests depletion. The use of fibrinogen reduction as a marker for DIC has been questioned because there are numerous other factors that can reduce fibrinogen.

TREATMENT:

Ultimately what all this clotting and bleeding comes down to is loss of blood flow to the tissues and treatment centers on restoring normal circulation.

This means intravenous fluid administration is crucial to restore tissue perfusion. Often plasma transfusion are used to replenish consumed blood clotting proteins. Plasma is often incubated with an anticoagulant substance called “heparin” before it is administered. Heparin activates anti-thrombin, which, as mentioned, has been depleted in DIC.

The most significant factor in the treatment of DIC is removal of the original disease that predisposed the patient to DIC in the first place. If this can be achieved, it would be the best chance at resolving DIC.

Posted by: **jenvetadmin** on Sat Feb 07, 2009 3:01 am

SINONASAL ASPERGILLOSIS GENERAL INFO:
Sinonasal aspergillosis is the most common manifestation of the Aspergillus infection. Most infections are invasive actually destroying the delicate bones of the sinuses while less invasive (and very rare) infections form a big mucous wad of fungus called a “fungal ball” or “aspergilloma.”
Clients generally notice a thick nasal discharge that has a strong odour, lasts for months, is non-responsive to antibiotics, and classically only comes from one nostril.
Epistaxis occurs intermittently and the edges of the nostrils are often ulcerated. Classically, the affected dogs are generally doliciocephalic although in one study, retrievers and rottweilers showed highest numbers (possibly suggesting they do more sniffing in fungal contaminated areas). Any age dog could be come infected.
To diagnose sinonasal aspergillosis two out of the following criteria must be met:
Radiographs or other imaging (CT or MRI) should be compatible with a fungal infection.
Fungal plaques should be visible with rhinoscopy.
Aspergillus organisms are seen in (or cultured from) either a tissue biopsy or the nasal discharge.
A blood test is positive for antibodies against an Aspergillus species.
General anesthesia is necessary for imaging as well as for rhinoscopy. Most veterinary hospitals can manage nasal radiographs but rhinoscopy may require referral (though sometimes the yellow Aspergillus plaques can be seen with less specialized equipment).
The treatment of aspergillosis has been challenging for many years; fungal infections as a rule are slow to clear and for a long time the only available drugs had toxic side effects. Today, sinonasal aspergillosis has a good prognosis thanks to a unique treatment plan.
The patient is anesthetized and the back of the throat and is closed off with gauze and foley catheters. A 1% solution of clotrimazoleis infused into the nose and frontal sinuses. The solution incubates for an hour and the patient is periodically turned to be sure all the nooks and crannies of the sinuses are treated. At the end of the incubation, the clotrimazole is drained through the nostrils and suctioned out.
This treatment is highly effective, with an 86% success rate though about 1/3 of patients require several treatments. Most of the time the nasal discharge has resolved within a couple of weeks but if there is still evidence of continuing infection one month after the treatment, the patient should be rechecked and another treatment should be expected.
If there is evidence that the infection has eroded through the sinus bones and has penetrated the brain, the treatment described above cannot be used and oral medication is needed. Common medications used are itraconazole and fluconazole. Several months of therapy is needed and a 60-70% success rate has been reported.

please comment in the forums is you use alternative treatments.

Do you feel you get value for money at your vets?