Internal Parasite Control
Mar 5, 2011 8:04:19 GMT 10
Post by Tom Meulman on Mar 5, 2011 8:04:19 GMT 10
These are notes from one of my lectures on intestinal parasites.
Parasite Control
Parasites may be divided into two groups, internal parasites and external parasites.
To treat both these groups effectively you need to know as much as you can about their life cycle, the part of the body they invade and the likely signs of their presence, particular during the summer months when both internal and external parasites tend to thrive.
The kennels and yards may also require treating when a severe infestation occurs.
Treatment of kennels and yards must be done in such a way, that any chance of toxicity to the greyhound is avoided.
There are two main categories of worms; they are Round - Hook & Whipworms (NEMATODES) and Tapeworms (CESTODES).
It is the Nematodes that cause the most amount of damage to the greyhounds system, mainly because part of their lifecycle involves travelling through the greyhound’s body, not just living in the gut or the intestines, even though that on its own is bad enough.
Roundworms
2 species, TOXASCARIS LEONIA and TOXASCARIS CANIS
Adults of both species are round, tapering to a point at each end, cream coloured, and may vary in length from 7 to 18 centimetres (3 to 7 inches)
Greyhounds become infested by swallowing the eggs of the ground in a contaminated yard, or even by licking contaminated dirt of their feet or coat.
Once ingested, the larva hatches out of the egg and start maturing into adults. It is probably interesting to note that it is in fact the dog’s own digestive juices that assist in the hatching process.
Toxascaris Leonia
The lava of this species burrows into the wall of the small intestine and in the process causes inflammation and interferes with the intestines ability to absorb nutrients effectively.
The most damage occurs in young pups, the typical signs are; thin potbellied pups, with a dry staring coat and a likelihood of intermittent diarrhoea or constipation.
Toxascaris Canis
These are the more common of the two species and the more dangerous to the health of the dog.
The larva of this species will penetrate the intestinal wall and migrate through the blood vessels to the lungs, once there, the inflammation they cause will make the pup cough, bringing the larva into the throat and they are then swallowed.
Re-entering the small intestine they mature into adults and continue the cycle.
Pups with large numbers of these parasites can die from the damage done by the larva.
The larva also migrate into the muscle tissue and other body organs where they may stay dormant for years, only being reactivated by a bitches pregnancy, pass across the uterus and infest the unborn puppies.
Due to this part of the worm’s life cycle many pups are born with roundworm infestation, making it imperative that all pups are wormed regularly.
Pups infested with Toxascaris Canis roundworm will not only have all the symptoms such as being thin with a potbelly, but will also have an intermittent cough and possibly laboured breathing, if enough lung damage has been done.
It takes only 3 weeks for roundworm larva to mature into adults and start laying eggs, for this reason worm the pups at two weeks of age and then every two weeks until at least 3 months of age.
Brood bitches must be wormed before whelping, preferably during the third to sixth week of pregnancy.
To reduce the chance of re-infestation, yards should be cleaned daily during the dry weather and twice daily when it is raining to avoid the eggs being washed into the soil. (That's what should be done but we all know it seldom happens)
Hookworms
3 species in total, 2 types of the ANCYLOSTOMA variety and 1 called UNCINARIA.
Hookworms are small worms, 7 to 16 millimetres in length as adults (5/16 to 5/8 inches) grey in colour until they drink blood when they will look red.
From all the worms that may affect a greyhound, hookworms can cause the most amount of damage due to the fact that they bite into the wall of the intestine and drink blood.
In many respects they resemble mosquitoes in this action, as in order to drink the blood, they first inject a substance that stops the blood from clotting.
Those of you that have greyhounds would have seen a greyhound puppy with a coat where much of the hair shows a distinct kink or hook at the end of each hair.
This is often seen in pups after they have been reared at a property where the soil has become severely contaminated by hookworm larva due to neglect by the proprietor.
It is the substance injected by the hookworm to keep the blood flowing that causes toxicity in the body and it is the toxicity that causes the hooky hair.
To a lesser extent this hooky hair is also seen in greyhounds suffering toxicity due to other causes.
The other interesting aspect of hookworm infestation is this: as you can imagine the greyhound is infested with hookworm and each of the adult worms is producing larva.
If all the larva so produced mature into adults and start drinking blood it would not be long before the host died, and all the worms along with it, not a very efficient way for a parasite to behave.
To stop this from happening the hookworm produces an enzyme in its faeces that stops the larva from maturing, and so limiting the number of adults.
This creates a problem when you treat the hookworm infestation, because the wormer will only kill the adult worms, once they are gone more larva’s mature, and the process starts all over again.
Therefore to treat a greyhound for a hookworm infestation, it is essential that the treatment be repeated every two weeks for a minimum of three doses.
Ancylostoma Hookworms
The larva of the Ancylostoma hookworm thrives in damp conditions, such as moist concrete and sand.
Greyhounds may become infested by eating the larva of the ground or by the larva penetrating the skin of the greyhound between the toes and the skin under the chest or abdomen.
Ingested larva enters the small intestine and develops into adults.
Some of the larva that enter via the skin, migrate through the blood stream to the lungs where they are coughed up and swallowed, again entering the intestine and maturing into adults, while other larva, after penetrating the skin lodge in the muscle tissue where they stay dormant until activated by late stage pregnancy.
They then make their way to the mammary gland, invade the milk, infesting the pups while they are suckling, making it a real possibility that pups at one month of age will be infested by adult worms.
As always the signs of an infestation are most severe in young puppies, as they cause massive blood loss and anaemia.
Pups with a severe infestation will show pale gums, weight loss, weakness, dry staring coat, and dark coloured manure due to the blood in it, and may die suddenly.
Uncinaria Hookworms
Greyhounds infested with this species of hookworm will show milder signs of infestation such as failure to thrive, poor coat and depression.
Greyhounds do acquire some resistance to repeat infestation of hookworm with age or after having been exposed to infective larva.
As always prevention from infestation requires cleanliness and good animal husbandry.
Contaminated yards maybe treated with a Chlorine spray, after which lime is raked through the soil and the yard rested for at least 4 weeks.
As mentioned earlier hookworm larva thrive on wet concrete, therefore in kennels where the floor is hosed daily to remove urine and faeces, and where there is poor ventilation a real chance exists of continuing infestation from hookworm larva.
Whipworms
Whipworms as their name implies have a thin front section and a thicker rear half and are 4 to 8 centimetres in length (11/2 to 3 inches).
The eggs of the Whipworm can survive in the soil or dirt in the kennels for several years and greyhounds become infested after eating the eggs off contaminated ground.
After ingestion the eggs hatch and within 6 weeks to 3 months, the larva’s develop into adult worms in the large intestine.
Heavy infestations cause signs of diarrhoea (sometimes containing blood), abdominal pain and weight loss. Because whipworms also suck blood from the greyhound a heavy infestation may also cause various degrees of anaemia.
Unlike round or hookworm infestations, the symptoms of the whipworm develop slowly over a period of 2 to 3 months and may therefore be easily misdiagnosed and treated as a basic health problem.
Diagnosis of whipworm infestation is made by finding the barrel-shaped eggs in a faecal examination.
Heartworm
Within the NEMATODE group of internal parasites is a blood parasite DIROFILARIA IMMITIS, commonly known as heartworm.
Heartworms are a major danger to greyhounds in areas of Australia where there are high temperatures, humid conditions and the presence of a certain species of mosquito.
While formerly limited to the northeastern states of Australia, the incidence of heartworm infestations appears to be spreading to the southern states.
This is aided by the fact that many trainers based in the south are taking their greyhounds north for specific races without taking the appropriate measures to protect their greyhounds against heartworm.
The parasite is a roundworm whose larval stage of its lifecycle is passed from greyhound to greyhound by a mosquito.
When a mosquito infected with the larva bites a greyhound the larva go into the tissue.
There in approximately 70 days, the larva goes through maturation stages and enters the blood vessels that carry the blood from the heart to the lungs.
Once there, the larva grow into adult worms that measure between 12 to 30 centimetres (4 to 12 inches) long and start producing larvae called MICROFILARIA in 85 to 192 days after the initial infection by the mosquito.
Heartworms cause inflammation of the blood vessel walls and partial blockage of blood flow and may survive for as long as 7 years.
A Greyhound may be infected with the adult worms for up to 9 to 10 months without showing any outward symptoms, while in the later stages of infestation performance will be compromised due to the reduced blood flow to the tissues.
Greyhounds may develop a chronic cough or may collapse or show weakness after a race or trial, the severity of the symptoms depending on the degree of blockage of the blood flow.
In addition the right side of the heart enlarges and may result in fluid accumulation in the lungs, kidneys and liver.
A worsening of the symptoms is seen when adult worms die or are killed by medication, due to worm fragments blocking blood flow in the lungs, resulting in severe coughing, bringing up blood tinged fluids from the lungs and difficulty in breathing.
These greyhounds will need immediate care by a Veterinarian as heart failure may occur and sudden death of the greyhound.
A diagnosis of heartworm infestation is made by either detecting the microfilaria in a blood test or testing for the antigens produced by the adult worms.
Prevention of heartworm infestation is a far better option that trying to treat an affected greyhound.
A once a month dose of IVERMECTIN (Heartgard) prevents heartworm disease by destroying the larva up to one month after an infective mosquito bite, the dose depending on the greyhound’s weight.
MILBEMYCIN OXIME (Interceptor) not only prevents heartworm disease by eliminating the larva, but also treats hookworm infestation, and is suitable for pups from 8 weeks of age.
Cestodes
Tapeworms, 3 species, TAENIA SPECIES, DIPYLIDIUM CANIUM and HYDATID SPECIES
Greyhounds become infested with the Taenia tapeworm by eating meat from infested sheep and cattle, or by eating rodents or rabbits. The more common tapeworm Dipylidium Caninum infests the greyhound when they bite at and ingest fleas or lice.
Many people have the habit of picking a flea off their dog and squashing it between the fingernails, I doubt they would continue to do so if they realized that that is the surest way of getting tapeworms themselves.The Hydatid tapeworm infests the greyhound when they eat offal from infected sheep.
You can tell by the appearance of the tapeworm segments which species has infested your greyhound. The first species the Taenia tapeworm has flat, thin white segments; the second species the tapeworm Dipylidium has pink moving segments about 1 centimetre in length. The Hydatid tapeworm has extremely small pink segments similar to the Dipylidium species but only about one-quarter the size.
These segments may be noted in the manure of infested greyhounds, or if the infestation is severe, on the hair around the anal area.
While the tapeworm does no specific structural damage to the intestines or the organs, the reality is that a tapeworm does a lot of harm to the general health of the greyhound.
The tapeworm is nothing more than a factory producing eggs; the head of the tapeworm is embedded in the wall of the gut, while the rest of the worm extends throughout the intestines.
The tapeworm has no gut, no intestines, it does not eat food, but absorbs nutrients and amino acids directly into its body, and those nutrients are no longer available to the greyhound.
Because a tapeworm is about 40% nervous system, the main nutrients it takes away from the greyhound are those amino acids required for building and maintaining a healthy nervous system.
A common reason for pups that are reared while infested with tapeworm, being more nervy and timid than their littermates.
Parasite Control
Parasites may be divided into two groups, internal parasites and external parasites.
To treat both these groups effectively you need to know as much as you can about their life cycle, the part of the body they invade and the likely signs of their presence, particular during the summer months when both internal and external parasites tend to thrive.
The kennels and yards may also require treating when a severe infestation occurs.
Treatment of kennels and yards must be done in such a way, that any chance of toxicity to the greyhound is avoided.
There are two main categories of worms; they are Round - Hook & Whipworms (NEMATODES) and Tapeworms (CESTODES).
It is the Nematodes that cause the most amount of damage to the greyhounds system, mainly because part of their lifecycle involves travelling through the greyhound’s body, not just living in the gut or the intestines, even though that on its own is bad enough.
Roundworms
2 species, TOXASCARIS LEONIA and TOXASCARIS CANIS
Adults of both species are round, tapering to a point at each end, cream coloured, and may vary in length from 7 to 18 centimetres (3 to 7 inches)
Greyhounds become infested by swallowing the eggs of the ground in a contaminated yard, or even by licking contaminated dirt of their feet or coat.
Once ingested, the larva hatches out of the egg and start maturing into adults. It is probably interesting to note that it is in fact the dog’s own digestive juices that assist in the hatching process.
Toxascaris Leonia
The lava of this species burrows into the wall of the small intestine and in the process causes inflammation and interferes with the intestines ability to absorb nutrients effectively.
The most damage occurs in young pups, the typical signs are; thin potbellied pups, with a dry staring coat and a likelihood of intermittent diarrhoea or constipation.
Toxascaris Canis
These are the more common of the two species and the more dangerous to the health of the dog.
The larva of this species will penetrate the intestinal wall and migrate through the blood vessels to the lungs, once there, the inflammation they cause will make the pup cough, bringing the larva into the throat and they are then swallowed.
Re-entering the small intestine they mature into adults and continue the cycle.
Pups with large numbers of these parasites can die from the damage done by the larva.
The larva also migrate into the muscle tissue and other body organs where they may stay dormant for years, only being reactivated by a bitches pregnancy, pass across the uterus and infest the unborn puppies.
Due to this part of the worm’s life cycle many pups are born with roundworm infestation, making it imperative that all pups are wormed regularly.
Pups infested with Toxascaris Canis roundworm will not only have all the symptoms such as being thin with a potbelly, but will also have an intermittent cough and possibly laboured breathing, if enough lung damage has been done.
It takes only 3 weeks for roundworm larva to mature into adults and start laying eggs, for this reason worm the pups at two weeks of age and then every two weeks until at least 3 months of age.
Brood bitches must be wormed before whelping, preferably during the third to sixth week of pregnancy.
To reduce the chance of re-infestation, yards should be cleaned daily during the dry weather and twice daily when it is raining to avoid the eggs being washed into the soil. (That's what should be done but we all know it seldom happens)
Hookworms
3 species in total, 2 types of the ANCYLOSTOMA variety and 1 called UNCINARIA.
Hookworms are small worms, 7 to 16 millimetres in length as adults (5/16 to 5/8 inches) grey in colour until they drink blood when they will look red.
From all the worms that may affect a greyhound, hookworms can cause the most amount of damage due to the fact that they bite into the wall of the intestine and drink blood.
In many respects they resemble mosquitoes in this action, as in order to drink the blood, they first inject a substance that stops the blood from clotting.
Those of you that have greyhounds would have seen a greyhound puppy with a coat where much of the hair shows a distinct kink or hook at the end of each hair.
This is often seen in pups after they have been reared at a property where the soil has become severely contaminated by hookworm larva due to neglect by the proprietor.
It is the substance injected by the hookworm to keep the blood flowing that causes toxicity in the body and it is the toxicity that causes the hooky hair.
To a lesser extent this hooky hair is also seen in greyhounds suffering toxicity due to other causes.
The other interesting aspect of hookworm infestation is this: as you can imagine the greyhound is infested with hookworm and each of the adult worms is producing larva.
If all the larva so produced mature into adults and start drinking blood it would not be long before the host died, and all the worms along with it, not a very efficient way for a parasite to behave.
To stop this from happening the hookworm produces an enzyme in its faeces that stops the larva from maturing, and so limiting the number of adults.
This creates a problem when you treat the hookworm infestation, because the wormer will only kill the adult worms, once they are gone more larva’s mature, and the process starts all over again.
Therefore to treat a greyhound for a hookworm infestation, it is essential that the treatment be repeated every two weeks for a minimum of three doses.
Ancylostoma Hookworms
The larva of the Ancylostoma hookworm thrives in damp conditions, such as moist concrete and sand.
Greyhounds may become infested by eating the larva of the ground or by the larva penetrating the skin of the greyhound between the toes and the skin under the chest or abdomen.
Ingested larva enters the small intestine and develops into adults.
Some of the larva that enter via the skin, migrate through the blood stream to the lungs where they are coughed up and swallowed, again entering the intestine and maturing into adults, while other larva, after penetrating the skin lodge in the muscle tissue where they stay dormant until activated by late stage pregnancy.
They then make their way to the mammary gland, invade the milk, infesting the pups while they are suckling, making it a real possibility that pups at one month of age will be infested by adult worms.
As always the signs of an infestation are most severe in young puppies, as they cause massive blood loss and anaemia.
Pups with a severe infestation will show pale gums, weight loss, weakness, dry staring coat, and dark coloured manure due to the blood in it, and may die suddenly.
Uncinaria Hookworms
Greyhounds infested with this species of hookworm will show milder signs of infestation such as failure to thrive, poor coat and depression.
Greyhounds do acquire some resistance to repeat infestation of hookworm with age or after having been exposed to infective larva.
As always prevention from infestation requires cleanliness and good animal husbandry.
Contaminated yards maybe treated with a Chlorine spray, after which lime is raked through the soil and the yard rested for at least 4 weeks.
As mentioned earlier hookworm larva thrive on wet concrete, therefore in kennels where the floor is hosed daily to remove urine and faeces, and where there is poor ventilation a real chance exists of continuing infestation from hookworm larva.
Whipworms
Whipworms as their name implies have a thin front section and a thicker rear half and are 4 to 8 centimetres in length (11/2 to 3 inches).
The eggs of the Whipworm can survive in the soil or dirt in the kennels for several years and greyhounds become infested after eating the eggs off contaminated ground.
After ingestion the eggs hatch and within 6 weeks to 3 months, the larva’s develop into adult worms in the large intestine.
Heavy infestations cause signs of diarrhoea (sometimes containing blood), abdominal pain and weight loss. Because whipworms also suck blood from the greyhound a heavy infestation may also cause various degrees of anaemia.
Unlike round or hookworm infestations, the symptoms of the whipworm develop slowly over a period of 2 to 3 months and may therefore be easily misdiagnosed and treated as a basic health problem.
Diagnosis of whipworm infestation is made by finding the barrel-shaped eggs in a faecal examination.
Heartworm
Within the NEMATODE group of internal parasites is a blood parasite DIROFILARIA IMMITIS, commonly known as heartworm.
Heartworms are a major danger to greyhounds in areas of Australia where there are high temperatures, humid conditions and the presence of a certain species of mosquito.
While formerly limited to the northeastern states of Australia, the incidence of heartworm infestations appears to be spreading to the southern states.
This is aided by the fact that many trainers based in the south are taking their greyhounds north for specific races without taking the appropriate measures to protect their greyhounds against heartworm.
The parasite is a roundworm whose larval stage of its lifecycle is passed from greyhound to greyhound by a mosquito.
When a mosquito infected with the larva bites a greyhound the larva go into the tissue.
There in approximately 70 days, the larva goes through maturation stages and enters the blood vessels that carry the blood from the heart to the lungs.
Once there, the larva grow into adult worms that measure between 12 to 30 centimetres (4 to 12 inches) long and start producing larvae called MICROFILARIA in 85 to 192 days after the initial infection by the mosquito.
Heartworms cause inflammation of the blood vessel walls and partial blockage of blood flow and may survive for as long as 7 years.
A Greyhound may be infected with the adult worms for up to 9 to 10 months without showing any outward symptoms, while in the later stages of infestation performance will be compromised due to the reduced blood flow to the tissues.
Greyhounds may develop a chronic cough or may collapse or show weakness after a race or trial, the severity of the symptoms depending on the degree of blockage of the blood flow.
In addition the right side of the heart enlarges and may result in fluid accumulation in the lungs, kidneys and liver.
A worsening of the symptoms is seen when adult worms die or are killed by medication, due to worm fragments blocking blood flow in the lungs, resulting in severe coughing, bringing up blood tinged fluids from the lungs and difficulty in breathing.
These greyhounds will need immediate care by a Veterinarian as heart failure may occur and sudden death of the greyhound.
A diagnosis of heartworm infestation is made by either detecting the microfilaria in a blood test or testing for the antigens produced by the adult worms.
Prevention of heartworm infestation is a far better option that trying to treat an affected greyhound.
A once a month dose of IVERMECTIN (Heartgard) prevents heartworm disease by destroying the larva up to one month after an infective mosquito bite, the dose depending on the greyhound’s weight.
MILBEMYCIN OXIME (Interceptor) not only prevents heartworm disease by eliminating the larva, but also treats hookworm infestation, and is suitable for pups from 8 weeks of age.
Cestodes
Tapeworms, 3 species, TAENIA SPECIES, DIPYLIDIUM CANIUM and HYDATID SPECIES
Greyhounds become infested with the Taenia tapeworm by eating meat from infested sheep and cattle, or by eating rodents or rabbits. The more common tapeworm Dipylidium Caninum infests the greyhound when they bite at and ingest fleas or lice.
Many people have the habit of picking a flea off their dog and squashing it between the fingernails, I doubt they would continue to do so if they realized that that is the surest way of getting tapeworms themselves.The Hydatid tapeworm infests the greyhound when they eat offal from infected sheep.
You can tell by the appearance of the tapeworm segments which species has infested your greyhound. The first species the Taenia tapeworm has flat, thin white segments; the second species the tapeworm Dipylidium has pink moving segments about 1 centimetre in length. The Hydatid tapeworm has extremely small pink segments similar to the Dipylidium species but only about one-quarter the size.
These segments may be noted in the manure of infested greyhounds, or if the infestation is severe, on the hair around the anal area.
While the tapeworm does no specific structural damage to the intestines or the organs, the reality is that a tapeworm does a lot of harm to the general health of the greyhound.
The tapeworm is nothing more than a factory producing eggs; the head of the tapeworm is embedded in the wall of the gut, while the rest of the worm extends throughout the intestines.
The tapeworm has no gut, no intestines, it does not eat food, but absorbs nutrients and amino acids directly into its body, and those nutrients are no longer available to the greyhound.
Because a tapeworm is about 40% nervous system, the main nutrients it takes away from the greyhound are those amino acids required for building and maintaining a healthy nervous system.
A common reason for pups that are reared while infested with tapeworm, being more nervy and timid than their littermates.