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The
PetStuff Online Newsletter
Visit Dr Dan's New Bulletin Board!
Chat With Dr Dan
Well, I've learned lots of things this past week. I "hope" to never reveal your names on the mailing again like last week. We have new mailing software, but I don't have the kinks figured out yet. Please bear with me while I learn. I know the "vet med" end of it, but I'm a horrible neophyte dealing with the capabilities of the Internet. Who knows, maybe in 6 months I'll be doing real time movies of surgeries! I also became aware that AOL and other ISP's won't allow graphics to come through. Jerks! With no graphics this newsletter is like black and white TV! So if they don't come through this week I will get the newsletter posted on my web site with a link to it. Please let me know if you don't get the graphical version. I want to announce my new Bulletin Board. It is hosted (eg for free) by my ISP and is soooo cool. I really like the new technology they used. Please fill it up with your pet questions. I think you will love the way it works with search capabilities, etc. Hope to talk with ya there soon. Address is: http://www.petinfoforum.com If you have friends that might like to receive the PetStuff Newsletter tell them to send me an email with "ADD" in the subject line or "heaven forbid" if you want to be removed just put "REMOVE" in the subject line. news@dr-dan.com As usual, I'm out of time and have to get this off, so away we go... Promise it will keep getting better!
"Roundworms and Their Public Health Significance" This week we would like to discuss an extremely common intestinal parasite of dogs and cats and many other animals. Almost all mammals can have some form of roundworms. Typically, these are the "spaghetti-like worms" you can see in the vomitus and feces of puppies and kittens. Since they can cause serious problems in humans (usually children) I wanted to bring attention to the dangers they can present. What are they? How do our pets get
roundworms? A second source of infection is through the mother's milk - Roundworm larva can gain entry into the mammary glands and then be passed to the puppies or kittens as they nurse. A third possibility is if the young animal should eat an embryonated egg found in fecal contamination of food or water bowls, the nesting box or other environmental sources. The egg hatches within the intestine and a "Blood-Lung" migration begins as described below. In the three cases above we are talking about a "Blood-Lung" migration. In other words, from wherever the roundworm larva gains entry into the pet's body the larva then migrate to the liver via the portal blood system (the portal blood system is the one draining from the stomach, intestines and leading to the liver) . The larva are then carried by the circulatory system to the lungs where they can pierce the walls of tiny lung blood vessels (capillaries) and gain entry into the airways (alveoli and bronchioles). The cilia (little whiskers that move foreign objects) lining the airways then move the larva up the bronchi and windpipe until they are coughed up and swallowed. Once they are swallowed they have become large enough that they can continue their maturation to adult egg-laying roundworms in the small intestine. Somatic cycle... A second type of roundworm life cycle occurs when dogs or cats develop "age resistance" at about 6 months of age or older. Instead of the larval form reaching the lungs via the blood and going through the "coughing up, swallowing and growing to adult in the intestine" phase another phenomenon occurs. The so-called "age resistance" alerts the dog or cats immune system to the possible presence of roundworm larva. When a larva enters the body, the immune system traps it in walled-off granuloma's that may appear in nearly any tissue. I have personally seen them in liver tissue when doing post-morteum exams. Once trapped in granuloma's, the larva can live for years occasionally escaping to become re-trapped in other granuloma's. During the last 1/3 of pregnancy this migration of these juvenile roundworms is greatly accelerated allowing them to find their way into the placenta and fetus or into the mammary glands to infect nursing puppies. When the bitch cleans the puppies she also may swallow infective eggs. Complicated isn't it? Maybe a graphic will help...
What are the
signs of roundworm infestation? More important to the pet's health are the migrating juveniles. As they pass thru the liver and lungs they can cause verminous pneumonia or hepatitis. Signs of roundworm infestation include: dull hair coat, pot-bellied unthrify appearance, poor weight gain, vomiting, coughing, intermittant diarrhea or constipation. Heavily infested puppies or kittens occasionally die of worm-related pneumonia. What is the treatment? So what's the big deal
with public health significance? Once the embryonated roundworm egg reaches the intestine of the human it hatches and the larva penetrates the intestine wall. From there it gains entry into the blood stream and may end up just about anywhere in the body including vital organs such as the eye, brain, liver, kidneys, heart wall, lungs, etc. Since humans are an unnatural host for the roundworm larva, their body reacts and walls off the larva in little granuloma's (similar to what occurs in adult dogs and cats). These granuloma's may cause sudden dysfunction of any of these organs resulting in illness. The most often diagnosed illness is loss of sight in one eye. The roundworm larva is trapped in the optic disk behind the retina of the eye and a granuloma forms. These granuloma's have been mistaken for retinoblastoma's (cancer of the retina) and the eye was mistakenly removed. I believe the reason the problem is so often diagnosed in the eye is because we know it is happening. We experience loss of vision; the eye is removed and the larva is discovered. Remember what I said above? When roundworm larva are encased in granuloma's they are impossible to kill with any anti-parasitic drugs and they are also impossible to detect. How many cases of persons seizuring with no apparent cause could be related to roundworm larva? It is impossible to know because the granuloma's are impossible to detect. We can't remove the brain and search for the larva microscopically. I hope I didn't scare you by making you aware of this problem. The problem is rare, but it "can" happen at any time. This is an important reason for people to always wash their hands before eating or putting a finger in the mouth. Who knows, it could save your eye! Be Safe - Be Sure - Have Your Vet Check Your Pet for Intestinal Worms Twice a Year!
Next Week I would like to continue on with the subject of the worms of dogs and cats and how they can affect humans. Here is the schedule. August 27th -
Hookworms and Why Dogs Are Kept off Beaches
A Little Pet Humor in Closing Cat Rules The Vacuum Cleaner Bad Dog A list of phrases dog
owners should get their naughty pets to write on the Blackboard 100 times...
Credits Images used in this publication taken from Hill's Atlas of Clinical Anatomy, Published by Veterinary Medicine Publishing Company, Inc. A publication used by veterinarians to teach their clients about their dogs and cats in sickness and health.
Have A Good Week Later, Dr Dan
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