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SDAV in the Rat Hobbyists Rattery by Debbi J. Needham

SDAV in the Hobbyists Rattery by Debbi J.Needham
1st posted 2001 - Reposted 2010

Two weeks ago you rescued a cute helpless rat from the pet store. It seemed a little bit depressed, but nothing was obviously wrong
with it. It sneezed for a bit and had a little discharge around its eyes. A week later it is still hanging in there, but now some of your other
rat's are sneezing. What is happening you ask?

It is very possible your rattery has contracted a very contagious, possibly lethal viral disease called Sialodacryoadentis virus, SDA
virus or SDA. It is a common, fast spreading rat virus that affects both fancy rats and laboratory rats.
The virus belongs to a group of corona viruses that effect the respiratory tract in rats (4).
In this article, I hope to elaborate on the virus, its symptoms, how it is transmitted, treatment and prevention.

SYMPTOMS
The severity of symptoms vary for each individual rat. Rats infected will show at least one of the following symptoms if not a combination
of them. The first symptoms will appear three to seven days after exposure (4).

a. Sneezing with or without runny nose.
b. Squinting or rubbing of eyes or nose. Possible corneal ulceration from dry eyes.
c. Swelling around the head caused by cervical edema and enlarged salivary glands and lymph nodes or "chipmunk cheeks".
d. Bilateral or unilateral ocular swelling or "buldging eyes" (1,3,4).

Most rats appear depressed during the symptomatic stage of the virus. They will rub their eyes, ears and nose with their paws (1).
They will slow their eating and drinking and appear to sleep a lot (1,3,4). Not all rats will show these signs (1,3,4).
Within 30 days, all of the symptoms are usually gone (1,3).
Please note that a poryphrin discharge from eyes and nose is possible, but it is not characteristic for this virus (4).

Although rats may show signs of this disease for several weeks, the virus is actually present in the tissues of infected rats
for only five to seven days. (1,2,3,4). It will spread during that period.

After recovery, the infected rat has immunity to the virus for up to 15 months and will not usually show clinical signs if reinfected (1,3).
Although they may not show symptoms if they are re-affected, they can still transmit the virus to other rats (1,2,3,4).
There is no carrier state there-after (1). However, quarantining the rattery from any incoming or outgoing rats for six to eight weeks is
advised to insure that the virus does not keep spreading to new hosts (1,2,3).

My rattery was infected with the virus in Early 2001. I brought it home on my clothes after visiting a rattery that harbored the virus.
Within five days, the symptoms appeared in some of my rats. They showed symptoms ranging from mild to severe. The majority of my
dumbo rats had swelling around their eyes and cheeks, making their eyes appear bulging. My standard, pregnant does, and juvenile
rats, from 5-8 mos, were the least affected. They did appear depressed and had fits of sneezing, but no facial abnormalities. Only a few
had discharge from the eyes and nose. My rats were depressed for three to five days before they appeared to recover. It was during this
phase of the disease that the few rats that refused to eat or drink and had laboured breathing, died. Some of my rats continued to eat and
drink normally through this period but they did show characteristic facial swelling and sneezing fits. The swelling was noticeably reduced
a week after it appeared. Newborn and nursing kittens that were infected had a high mortality rate (50%).
They were smaller than normal kittens and many had nasal congestion that I contribute to their failure to nurse, thus thrive.

TRANSMISSION
Transmission occurs very quickly through the air or by direct contact through nasal secretions (runny nose and sneezing), or saliva,
(sharing a water bottle), (1). The virus can live for up to three days on objects clothes and hands (7).
It is highly contagious and will spread through rooms within the same house or building within days.

Often laboratories inflicted with the virus, will actively infect their entire colony by adding one infected rat to a cage of non-infected.
This active exposure reduces the time of total infestation rather than allowing slower passive exposure.
Hypothetically it is possible that an object bought at a pet store can contain the virus and if given directly to the rat, infect it.
However, common detergents and disinfectants render it noninfectious (2). Wash all new objects before giving them to your rats.

At the time of the outbreak in my rattery, my rats were caged in pairs throughout the house. The SDAv virus spread from room to room
in my house within two weeks. The last rats it reached were in my quarantine room (my bathroom) and my upstairs rooms.

TREATMENT
During infection with SDAV, a rats immune system is suppressed, therefore allowing other infectious agents to gain footing.
These include Mycoplasma (2) Paseurella pneumotopica, Actinobacilus and Staphyloccoccus (3) bacteria.

At the very first sign of illness start treatment with antibiotics (3). Tetracycline or oxytetracycline is an effective antibiotic against bacterial
infections that affect rats (5). You can buy larges packages of it at feed stores as pet stores as fish and bird tablets or pills. Use 1/2 to 1
tsp per 8 oz. of water. This antibiotic is bitter so add sugar to the water and most rats will drink it (6). Treatment with a vaporizer can also
improve congestion and encourage eating. Ammonia build up from high concentrations of urine can irritate rats respiratory systems.
Change your rats bedding frequently through this illness. Bleach and scrub the cage bottoms, bars and ramps and rinse them well.

SUMMARY
SDAV is a serious illness that produces bizarre and shocking symptoms. According to the literature it is rarely fatal for rats in laboratories
(1,2,3,4). However, in the hobby population, it can be life threatening. Hobbyists are rarely able to replicate the sterile conditions in a
laboratory, neither do they have access to the life saving medications available to laboratories. Pet rats can quickly succumb to
secondary infections. Treat your rats with antibiotics immediately if you suspect your rat has this illness. Quarantine all new rats before
they come into your home in a separate building away from your colony for at least one to two weeks.

I gave tetracycline to the majority of my rats for two to three weeks following the onset of symptoms. I gave Baytril, by veterinary
prescription, to my pregnant or nursing does. I found using a vaporizer (or humidifier) for the rats with labored breathing on and off for an
hour, a couple of times a day, seemed to give them relief. Most rats recovered completely within two weeks. A couple of my rats
continued to have rattling sounding chests, most likely from scarring or Mycoplasma infections, thereafter.
These rats, I assumed, had lower immune systems, so I never bred from them.

PREVENTION
Prevention is a key factor in avoiding this illness. Immediately after visiting a rattery, take a shower and change your clothes.
Wash and disinfect all new rodent toys and cages before introducing them to your rats. Do not accept a rat from a breeder that is sneezing
or showing signs of illness. Quarantine all new rats in a separate building for a couple of weeks before introducing them to your rats.
Also quarantine show rats after a show in a separate area for two weeks prior to introducing them back into your rattery.

ARTICLE SOURCES

1)SialoDacryoAdentitis Virus, updated 2-14-200, UF News Events.
2)New Page 1 stolen from Charles River Technical Bulletin, Vol. 2, No. 2 Controlling the Spread of Infection of Sialodacryoadentitis
Virus, SDAV (rat corona virus).
3) The Biology and Medicine of Rabbits and Rodents (pgs 288-290). Date. Author. Publisher.
4) CRL - Techinal Bulletin. Oct. 1983: Rat Corona Virus.
5) National Fancy Rat Society, Respiratory Disease in Rats and Mice, 1998. Anne Storey MSC. FIBMS.
6) Rat and Mouse Gazette: Medical Corner: Drug Useage Chart for Rats. Mary Ann Isaksen and Daryl Mabley DVM.
(Revised by m. Isaksen, July 2000). From July/August Issue.
7) Veterinary Medical Journal (pgs ) Author. Date. Publisher.