ROUNDWORMS
A severe infestation of larval-phase roundworms can cause liver, lung and brain damage. A heavy accumulation of roundworms in a puppy can lead to death. Symptoms include vomiting, colic, poor growth and a "pot-bellied" appearance.

Almost all puppies are born with roundworms or acquire them through their mother's milk. Though most adult roundworms are expelled by dogs by the age of six months, a large proportion of adult dogs continue to have light infestations. Matters can be further complicated by the larvae which can remain "dormant" in tissues until the mother dog is pregnant.

Treating Roundworm Infection
It is very important to be sure that your dog is tested for possible roundworm infection before starting a prevention routine. 

How Roundworms are Transmitted
The most common method of roundworm transmission is when a puppy nurses from the infected mother dog. In addition, roundworms can be transmitted through the faeces of dogs, but dogs can also acquire roundworm infection through contact with soil containing these eggs. Moreover, roundworms can be transmitted when a dog eats an infected rodent.

Understanding the Life Cycle of the Roundworm: 
The key to elimination is to understanding the life cycle of the roundworm. This helps to show how proper treatment can eradicate the problem.

Roundworm Eggs
Adult roundworms live in the small intestine of dogs, where they lay up to 80,000 eggs per day. The eggs are released with the dog's faeces, where they then dwell. The larvae develop inside the eggs while the eggs are located in the expelled faeces.

Roundworm Transmission and Growth
As the larvae grow within the eggs, the dogs may ingest the un-hatched eggs in the environment or the dog may eat an infected rodent. These eggs hatch within the dog, where the larvae develop in the stomach before moving to the small intestine. Puppies can become infected before birth by having the larvae migrate from the placenta to the liver, from the liver to the lungs, and from the lungs up the trachea and then down to the stomach. 

Adult Roundworm
The larvae mature within the stomach and small intestine into egg-laying adults.

HOOKWORMS
The hookworm's voracious appetite for blood can quickly cause severe anaemia and/or death in a dog. Infestation of 500 worms can cause a five-pound puppy to lose half its total blood volume in one day. As few as 100 hookworms can cause a puppy to die of blood loss.
Hookworms attach themselves to a dog's intestinal lining with hook-like teeth, leaving bleeding internal wounds that are particularly dangerous to puppies. Relatively small (1/4 to 3/4 of an inch long), hookworms are dangerous to all dogs – puppies in particular. 

How Hookworms are Transmitted
The most common method of hookworm transmission is through the faeces of dogs. Hookworm eggs pass through the faeces of infected dogs and hatch into larvae. These larvae can be swallowed by a healthy dog or penetrate through the dog's skin or foot pad. Mother dogs can give hookworms to their puppies through their milk.

Hookworm Eggs 
Adult hookworms live in the small intestine of dogs, and they lay up to 50,000 eggs per day. The eggs are released with the dog's faeces, where they then dwell.
 
Hookworm Larvae
Within animal faeces, the hookworm eggs hatch and develop into larvae. Dogs can be infected through the ingestion of these larvae or from larvae puncturing the pet's foot pad. Once internalised, the larvae migrate to the small intestine.

Adult Hookworm
It is within the small intestine that the hookworms mature into adults. The eggs can again be released into the dog's faeces or immature larvae can be passed directly from the mother dog to its nursing pups.

WHIPWORMS 
Whipworm infection causes bloody diarrhoea, weight loss, anaemia and dehydration, but diagnosis is very difficult and may require several exams. Symptoms include diarrhoea, abdominal pain and mucus-laden stools streaked with blood. A large number of worms (more than 2,000 in some cases) can cause anaemia.
 

Whipworms, 1.75 to 3 inches long, reside in the large intestine and cecum. Using its mouth as a spear-like sword, the whipworm slashes and punctures the intestine and then feeds on the released blood and tissue fluids.

How Whipworms are Transmitted
The most common method of whipworm transmission is through the faeces of dogs, but it is also suspected that they may be transmitted through soil. The eggs that pass through the faeces can be swallowed un-hatched by a healthy dog, where they will hatch inside.

Whipworm is difficult to control outside the dog. Whipworm eggs pass into the soil, where they can survive for years under the most severe weather conditions. Whipworm eggs are virtually impossible to attack chemically (the ova may be absent from faeces in many infected dogs).

Whipworm Eggs
Adult whipworms live in the cecum of dogs, where they lay eggs. The eggs are released with the dog's faeces, where they then dwell. The larvae develop inside the eggs.

Whipworm Transmission and Growth As the larvae grow within the eggs, the dogs may ingest the un-hatched eggs. 

Adult Whipworm 
These eggs hatch within the dog, where the larvae mature into adults, which then lay eggs to begin a new the life cycle.

TAPEWORMS
Tapeworms are large worms that live in the gut of dogs. They may migrate about in the area around the dog's anus which can lead to irritating itching and thus bad hygiene by the dog. Tapeworms often have an intermediate host in addition to their final host (the dog). The most important intermediate hosts of canine tapeworms are fleas or certain mammals like sheep and rabbits.

How Tapeworms Are Transmitted 
The most common canine tapeworm is transmitted by fleas. Flea larvae become infected by ingesting tapeworm eggs that have been shed in the dog's faeces. Dogs become infected if they swallow an infected flea while grooming. The tapeworms grow to maturity in the dog's gut. Tapeworm segments which contain eggs are then shed in the dog's faeces. Tapeworms also can be transmitted when dogs eat the raw meat of infected intermediate hosts.

Tapeworm Eggs
Adult tapeworms live in the guts of dogs, where they lay their eggs. The eggs are released with the dog's faeces, where they then dwell.

Tapeworm Transmission and Growth
As the larvae grow within the eggs, the eggs may be ingested by flea larvae that are also present in the dog faeces. If a dog ingests an infected flea, the tapeworm larvae may hatch and mature in the gut of the dog.

Adult Tapeworm
The larvae mature within the gut of the dog where they may travel as far down as the anus. They generally lay their eggs in the gut.

NOTE:  
Veterinarians typically agree that testing for worms and following a good de-worming program is essential for puppies. After your veterinarian has de-wormed your puppy or dog, do not be alarmed at the stool immediately following the medication. The worms are expelled over a 24 to 48 hour basis and the stool may be full of worms. Do not be alarmed -- this is normal.