Worms (new)

Worms (new)

Round worms

(c) Dr. John W. McGarry and the School of Vet Science in Liverpool

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Following worms are described below:

Liver flukes, Tape worms, Lung worms, Round worms

For Eye worms - see under Eye problems

Liver Flukes

Local names: 
Embu: nthambara / Gikuyu: thambara cia mani / Kamba: ntambaa / Kipsigis: sungurutek / Luo: ochwe / Maragoli: ovoveyi / Meru: nthanthara / Samburu: ikurui, lemonyua / Somali Ethiopia: faraqle / Somali Kenya: sogul / Masai: Osinkirri 
 
Family: Trematoda 
Description: Parasite 


Introduction

There are two important species of liver flukes in Kenya: fasciola gigantica and fasciola hepatica. The former is more important, being found throughout the lower warmer parts of the country. As the name suggests it is very large, more than twice the size of fasciola hepatica, which is found in the cooler highland areas of the country, and also in the temperate zones of the world such as Europe, North America, Australia and New Zealand.
 
The life cycle of liver flukes involves a snail, which acts as an intermediate host. If there is no snail there will be no flukes. The snail involved requires still, stagnant water to survive; swift running water does not suit it. Swamps, ponds, lakes with a marshy edge and pools of water edged by vegetation are danger zones for grazing animals.
 
Cattle, sheep and goats are mainly affected, although other animals such as donkeys, horses, and many species of wildlife such as buffalo can also be infested. Humans can also be infested with liver flukes.
 
As the name suggests, the liver fluke attacks the liver.

 

Three forms of illness can occur:
 
  1. Flukes can cause sudden death, from liver failure and from internal bleeding, when large numbers of immature flukes migrate through and cause damage to liver tissue. This clinical picture is common in young sheep.
  2. Flukes can also cause a chronic wasting disease accompanied by anaemia and oedema (swelling). The oedema is typically located on the lower jaws ("bottle jaw") and on the lower part of the belly. This is the most common picture in cattle.
  3. Liver lesions due to flukes are the causative factor in Infectious Necrotic Hepatitis (Black Disease), predominantly a disease of sheep aged between 2 - 4 years, but aso occurs in young cattle. Specific bacteria (Clostridia) multiply in liver lesions caused by migrating flukes and release toxins. Sudden death is the result.
 
 
Adult of Fasciola hepatica
(c) Wikipedia

 

Life cycle of liver flukes

Knowledge of the life cycle of the liver fluke is an aid in understanding how to control the disease.
 
The intermediate host snails for Fasciola gigantica and Fasciola hepatica may differ but in other respects the life cycle is the same.
 
  • The life cycle begins with the eggs of the fluke which mature in the bile ducts in the liver, pass down the ducts, into the gut and are excreted with the faeces.
  • Once outside in the environment, which must contain water, the eggs hatch, releasing an active stage, called miracidia. Temperature and time are critical in the early stages for the development of the miracidia- above 5-6 C, and best between 25-24C. Miracidia must find a suitable snail within 24-30 hours or they will die.
  • The miracidia either actively invade a host snail or are eaten by a host snail.
  • They then hatch in the snail's gut and the next stage develops in the tissues of the snail.
  • 5 to 8 weeks later another stage emerges from the snail and form resistant cysts attached to herbage or grass, where they are eaten by the final host - cattle, sheep, goat or other herbivores.
  • Once ingested by the sheep or cow the immature fluke invade the gut wall, travel to the liver where they cause extensive damage to the liver tissue until they reach the bile ducts. Here they mature into adult flukes and start to lay eggs and the life cycle begins again. It takes 10-12 weeks from infestation until eggs start to be laid and shed with the faeces.

Mature flukes are long lived and sheep and cattle may be carriers for years.

Lifecycle of Fasciola hepatica

(c) Grace Mulcahy

 

 

Life cycle of a liver fluke
(c) uk.merial.com

 

  

Signs of Liver Fluke disease

The severity of clinical signs depends on the number of parasites ingested by the host animal over a short period of time. Cattle appear to be able to develop an immune reaction to fluke infestation, but sheep do not.

The acute form of the disease is more common in sheep than in cattle.

  • It occurs 5 to 6 weeks after the ingestion of large numbers of metacercariae. There is a sudden invasion of the liver by masses of young liver flukes.
  • Sudden death, especially in sheep, can occur due to internal bleeding and liver failure and also due to sudden release of toxin by bacteria (Clostridia) multiplying rapidly in the liver lesions (Black Disease)
  • The acute form of the disease in cattle is manifested either by sudden death, or dullness, weakness, anaemia, lack of appetite, pain over the region of the liver and death in 48 hours.
  • Because this is caused by migrating flukes which have not yet begun to lay eggs, no eggs are found in the faeces at laboratory analysis; diagnosis is only possible by post mortem examination.
  • Post mortem will reveal a badly damaged, swollen liver with many small perforations and haemorrhages (internal bleeding spots). The liver tissue contains mini-tunnels formed by the migrating immature flukes, which are visible by the naked eye at careful close examination.

 

The sub-acute or chronic form of the disease is more common in cattle, but also occurs in sheep and can cause death in both. It is the result of activity of the adult flukes in the bile ducts, causing anaemia and protein leakage.

  • Body growth is reduced, there is loss of weight and often emaciation, oedema appear on the lower jaw (`bottle jaw`) and on the lower belly, there can be anaemia.
  • Diagnosis in the laboratory is made by finding fluke eggs in faecal samples.
  • A post mortem examination will reveal large mature flukes in the bile ducts, which in cattle are usually thickened and may be hardened in cattle, these bile duct changes are not seen in sheep.

 

Diagnosis

Acute fluke infestation usually kills younger animals, especially sheep. Age difference is helpful in making a diagnosis based on the clinical signs, grazing history, access to stagnant water, season (whether wet or dry), post mortem findings, the finding of immature or mature flukes and the demonstration of fluke eggs in faecal samples.


 

Prevention - Control - Treatment

Prevention and control

  • Control measures include treatment against flukes in affected animals and the prevention of livestock access to snail-infested pastures. In practice only the first of these is used in most cases.
  • Fencing off snail sites makes sense when the areas are small. Preventing livestock from drinking from ponds and stagnant water where they can feed from peri-aquatic vegetation infested by liver fluke cysts is an important measure. This an bee achieved by providing adequately maintained water troughs for watering of livestock with a good concreted area around them to prevent the area from becoming muddied. 
  • Drainage of pastures and paddocks is the best permanent solution, but may be costly.
  • Grazing livestock in Africa are more likely to contract liver flukes infestations during the dry season than in the wet, as during the dry season they enter snail infested flood zones and marshes which constitute dry season grazing reserves. In such situations it is advisable to keep animals out of such swamps for as long as possible so that fewer viable cysts are present on the herbage.
  • When entry to the swamp is unavoidable then the older cattle should go in first as they are much more resistant than the younger cattle, followed, last of all, by the most susceptible sheep and goats.
  • The prophylactic administration of specific drugs against flukes to those animals most at risk, can considerably reduce occurrence of the disease.

 

Treatment

The following drugs are effective in the treatment of Liver Flukes:

  • Triclabendazole and Fenbendazole should be given at the rate of 10mg and 8mg respectively per kg body weight by mouth.
  • Trodax or nitroxynil given at 34 % solution for cattle administered subcutenously at 1.5ml per 50kg body weight and may be repeated as may be necessary.
  • Oxyclozanide or Flukanide or Ranide are available from different pharmaceutical manufacturers and should be used according to the manufacturer's recommendation.

Tape worms (Flat worms)

 

Introduction

The term Tapeworm refers to the flat shape of the worm parasite.aTapeworms are flat. Their body consists of a chain of visible segments, occurring one after the other. Terminal mature segments contain worm eggs; they are disconnected and excreted and can be seen in the faeces of infected animals. When a tapeworm dies the whole long worm can be excreted in one piece. The head part contains hooks, or suckers. Tapeworm eggs are of microscopic size and invisible to the eye.

Adult tapeworms in the intestine have little effect on the health of adult farm animals. Large numbers of tapeworms in the intestines of young animals may cause stunting and occasionally trigger severe colic.

The general life cycle of tapeworms occurs in two hosts, the final host (e.g. dog) and the intermediate host (e.g. cow).

 

Life cycle of tapeworms that live in the intestines of cattle, sheep and goats

The eggs of mature tapeworms that live inside the intestine of a cow, sheep or goat (final host) can only develop into another adult tapeworm after going through an intermediate stage inside the organs of an intermediate host. The intermediate hosts of the common tapeworms of ruminants are small mites that live on the pasture and are ingested by the final host during grazing.

 

 

1. Monieza benedeni

Monieza is found in the intestine of cattle, sheep, goats and occurs in most parts of the world. The life cycle includes the final host (ruminant) and the intermediate host -  small mites living in large numbers on the pasture. These mites are eaten by grazing animals and develop in the intestine into adult tapeworms. The adult tapeworm is 1-6 meters long, 16mm wide and lives for only about 3 months in the final host.  When the tapeworm dies it is shed with the faeces.

 
 
Monieza tapeworm segments in calf dung- segments are wider than long Monieza in lamb intestine Knot of worms from intestine-segments are wider than long
(c) Sheelagh S. Lloyd (c) Sheelagh S. Lloyd (c) Sheelagh S. Lloyd

 

2. Avittelina species

These occur in the small intestines of cattle and other ruminants. They are present mainly in Africa and India. The adult tape worm measures about 3 meters long and 3mm wide.


3. Thysaniezia giardi

This occurs in the small intestine of cattle, sheep and goats, mainly in Africa. The life cycle is through oribatid mites.

 

Clinical signs of adult tapeworm infection

Tapeworms in the intestine of adult cattle, sheep or goats do not cause any serious disease. Very large numbers of tapeworms in the intestine of calves and lambs can lead to stunting, pot belly, diarrhoea and constipation and also colic due to obstruction of the intestinal passage.
 

Diagnosis

This is made by observing tapeworm segments in the faeces or intestines, or in the laboratory by checking under the microscope for the presence of tapeworm eggs in the faeces.

 

At slaughter

  • Tapeworms may be present in the intestine or in the bile ducts.
  • The carcass may be pale and thin
  • The walls of the intestines may show ulcerations and inflammation caused by hooks of tapeworms
  • Tapeworm segments or a whole adult tapeworm can be seen in the faeces.
     

Prevention and Treatment

There are no preventive measures against tapeworms living in the intestine of ruminants.

Treatment

As the tapeworm has a limited lifespan and is excreted with the faeces it is not necessary to treat adult cattle, sheep and goats against tapeworms. Treatment may become necessary in heavily infected young calves, lambs and kids. Some broad spectrum anthelmintics are also active against tapeworms (see below).

  • Use of anthelminthic drugs that also act on tapeworms is the only effective treatment method (read label and instructions carefully, some anthelminthic drugs have no effect on tapeworms!).
  • Niclosamide, Praziquantel, Albendazole, Fenbendazole, and Oxfenbendazole are effective against tapeworms in cattle, sheep and goats.

 

Tapeworm segments
Taenid segments on faeces 

Taenid eggs migrating away from the faeces (white arrows) leaving a trail of eggs on the ground (black arrows)

Tapeworm cyst in muscle A: head, B: bladder Tapeworm segment (longer than wide)
Pictures by Sheelagh (c) S. Lloyd  

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Tapeworms in intestines of dogs causing cysts in cattle, sheep and goats

  • Tapeworms living in the intestine of dogs are of great significance as they cause cysts and dangerous chronic disease in ruminants and also in humans.
  • Life cycle of tapeworms that live in the intestines of dogs and cause disease in cattle, sheep, goats and humans (!)

Dogs harbour specific tapeworms in their intestines and excrete the eggs into the environment, including onto pastures. Cattle, sheep, goats (and humans) are the intermediate hosts. If cattle, sheep and goats swallow tapeworm eggs excreted by dogs, the intermediate stages of these tapeworms develop into cysts inside the body of the cow, sheep, goat (or human). Depending on location of the cysts inside the body (often found in liver, lung, also in the brain) this has very serious effects on the health, leading to chronic and ultimately deadly disease.

The adult tapeworm lives in the intestine of the dog (final host) and produce eggs, which are excreted inside the tapeworm segments (called proglotid). After the segments have been shed with the faeces they disintegrate and release invisible eggs into the environment. These eggs can survive for a long time on the pasture. The invisible eggs are then eaten by the cow, sheep, goat (intermediate host) during grazing and transform into a cyst.

The most dangerous tapeworm found in dogs is Echinococcus. The adults of this small species of tapeworm live in the intestine of the dog (final host), causing almost no harm to the dog. Eggs are shed in dog faeces, then ingested by intermediate hosts (cattle, sheep, goats, humans) and develop into cysts in the organs of the intermediate host (esp. liver, lung, also brain). These so called hydatid cysts continue to grow and also form multiple daughter cysts, causing severe damage to the organs of the intermediate host.

When organs of the intermediate host containing cysts are ingested by dogs (e.g. at slaughter) the cysts will again develop into an adult tapeworm living inside the intestine of the final host (dog) and the cycle starts again.

In sheep, goats, cattle and also pigs Taenia Hydatigena larva (long necked bladder worm)causes large cyst of 5-8 cm in diameter, containing a clear watery fluid often attached to the liver.

(c) Dr. John W. McGarry and the School of Vet Science in Liverpool

 

 

1) Taenia hydatigena

This is a dog tapeworm and cattle, sheep, goats and also pigs are intermediate hosts. If dogs have access to the liver or peritoneal tissues of infected cattle they become infested with the adult tapeworm.

 

2) Larval tape worm infestation in cattle

A number of tapeworms are of significance as they involve humans and domestic dogs.

 

 
3. Echinococcus granulosus

This is a very small and short dog tapeworm.It is the most dangerous tapeworm of dogs because it forms many hydatid cysts that continue to grow in the organs of the intermediate hosts: sheep, goat, cattle and also humans. These cysts are mostly located in the liver and lungs, sometimes also in the brain. They can slowly grow to a very large size. People living in very close association with infected dogs are especially at risk.

 
Echinococcus hydatid liver cyst. Fluid filled large opaque cyst, the most common diameter being 5.0 - 10.0 cm. When mature, cysts may reach 0.5 meter in diameter depending on available space
(c) Dr. John W. McGarry and the School of Vet Science in Liverpool

 

Symptoms of Tapeworm cysts in the intermediate hosts

Tapeworms have no apparent effect in the dog (main host).

In intermediate hosts (sheep, goat, cattle, human) symptoms vary depending on the organ of the body which is affected. Coenurus cerebralis, can reach the brain of intermediate hosts and cause staggering, blindness, head deviation, stumbling and paralysis. This condition is known in livestock as gid or sturdy. Palpation of the skull may reveal a soft spot and in very few cases it may be possible for a skilled veterinary surgeon to remove the cyst. Echinococcus cysts cause symptoms that depend very much on the location of the cysts; symptoms can be central nervous (circling disease in sheep) or chronic, when cysts are located in the liver or lung.

 

Diagnosis

Lesions in livestock are normally found during meat inspection.

 

 

 

Prevention and control of Tapeworms in dogs

Dogs must never be fed raw slaughterhouse offal (lung, liver) or raw brain tissue from ruminants.

Dogs must be dewormed regularly (4xper year) with an anthelmintic drug that is effective against tapeworms (read label and instructions carefully, some anthelmintic drugs have no effect on tapeworms!).

After slaughter it is important to dispose of and/or destroy all condemned organs and tissues that contain cysts in such a way, that dogs and other scavengers (Hyena) cannot gain access.

 

Ensure the following:

  • Regular deworming of dogs against tapeworms
  • Good meat inspection procedures by qualified meat inspectors and destruction or correct and safe disposal of infected tissues and meat (dispose offals into deep concrete pit that can be closed properly)
  • Fencing of slaughter houses with dog proof fences will keep stray dogs away and prevent them from eating condemned meat that may be infected with cysts.
  • When living in association with dogs, observe strict personal hygiene: always wash your hands thoroughly with soap after having contact with the dog. Always wash your hands thoroughly with soap before preparing food or eating. Children playing with dogs are at a particularly high risk of infection! Infected dogs licking children's hands or faces can transmit the tapeworm eggs to them! Dogs living close to children must be dewormed very regularly.

 

Treatment of tapeworm cysts

 

Treatment of tapeworm cysts is not possible in livestock.

Treatment of hydatid cysts in humans is difficult and sometimes requires surgical removal of thr cysts. Treatment is not always successful - in such cases the disease is fatal - the patient dies!

 

Tapeworms in the intestines of humans

 

Taenia saginata

This is a tapeworm of humans, it causes abdominal discomfort. It is a very long tapeworm, growing up to 15 metres long. Cattle are the main intermediate hosts. In cattle the cysts are located in skeletal and heart muscle tissue where they appear as small white oval nodules, visible to the naked eye. These, if swallowed by a human, will again develop into a mature tapeworm. The tapeworm stage in cattle is also called measles. When measles are found at meat inspection the carcass can be detained and kept frozen below -10@C for minimum 10 days to destroy the cysts. Alternatively infected meat can also be properly cooked to make it safe for human consumption. Carcasses with measles are either condemned or fetch a very low price. Eating raw or undercooked meat that has not undergone meat inspection is highly dangerous and can result in infestation with Taenia saginata.  Most measles are found in the heart, tongue, diaphragm and cheek muscles of cattle.

Adult Taenia saginata tapeworm, note scale. Humans become infected by eating raw or undercooked infected meat. In the human intestine the cysts (larval stage) develop over 2 months into adult tapeworms which can survive for years. They attach to and feed from the small intestine.

@ Center for Disease Control CDC Atlanta/Geogia

Prevention

  • Use of pit latrines to keep human waste away from pastures and grazing animals. The public should also be enlightened about the dangers of using human waste as fertilizer.
  • Educating the public about the dangers of eating raw or partially cooked meat. The meat to be eaten by humans must be cooked properly or must be frozen below -10@C for minimum 10 days to kill the cysts.
  • Infected humans must be identified through laboratory tests and treated against tapeworms.

 

Round worms

Local names: 
Embu, Gikuyu, Meru: njoka / Gabbra: beni segara / Kamba: nzoka sya nda / Kipsigis: tiongik / Maragoli: tsinzoka / Samburu: ntumuai / Somali Ethiopia: goryan / Turkana: ngilomun /
Common names: : gastro-intestinal worms, gastro-intestinal Helminth, Nematodes
Description: Intestinal parasite, some are also found in the stomach

 

Introduction

Round worm infection, gastro-intestinal helminths or parasitic gastroenteritis, cause major economic loss in cattle, sheep and goat production.

The round worms are very small and vary in size from being visible to being almost invisible. - Several different species of worms with differing life cycles may be involved, but the symptoms they cause are all rather similar and difficult to differentiate in the living animal. Most round worms feed on nutrients inside the host animal's intestines. Certain worm species can attach to the lining of the stomach or guts, where they suck blood. These blood-sucking round worms cause more severe disease and anaemia and can kill young animals.

Immunity is acquired slowly and is generally incomplete. Good nutrition increases the resistance of livestock against round worms. Young animals are generally more at risk than adults. But in sheep and goats the adults remain susceptible and suffer more from the effects of worms than in cattle. Especially ewes after lambing harbour large numbers of worms and can show diarrhoea and a drop in milk yield due to lowered immunity against the worms.

When treating animals with symptoms, the following should be considered:

  • Provide adequate nutrition
  • Treat all animals in a group as a preventive measure in order to reduce further pasture contamination
  • Following treatment stock should NOT be moved to clean pasture as was previously recommended. The reason for this is that if any worms which are resistant to dewormers survive treatment then the clean pasture will become seeded with a completely resistant population of worms.

 

Resistance of worms against the drugs used (anthelmintic resistance) is a major and growing problem. Under-dosing, underestimation of body weight, overuse of anthelmintic drugs, random use of anthelmintics without a proper diagnosis, poor nutrition and rapid reinfestation all play a role in causing resistance. In some countries, such as Australia and South Africa, anthelmintic resistance is such a serious problem that it threatens the economic viability of sheep farming. In order to prevent such a situation from developing anthelmintics must be used correctly and with restraint.  A good strategy is NOT to deworm the whole herd but to rather target specific animals or groups of animals, examples:

  • Deworm young animals to prevent stunting
  • Deworm ewes at lambing
  • Selectively deworm those individual animals showing severe anaemia, visible as pale membranes around the eyes

Such a targeted deworming strategy will also reduce the amount of money spent on anthelmintics.

 

When suspecting resistance of worms against an anthelmintic drug the following test can be carried out:

  1. Immediately before deworming collect a pooled faecal sample from the group to be treated and send it to a laboratory for counting the number of worm eggs in the faeces (faecal egg count). This test is easy to perform in a lab and is not costly.
  2. 7-8 days after the treatment collect a second pooled faecal sample from the group and send it to the laboratory for a repeat faecal egg count.
  3. The comparison of worm egg numbers before and after the treatment will show whether the anthelmintic used is till effective or not.

 

Life cycle

The life cycle of the worms usually takes 2 to 3 weeks, but varies in relation to dry conditions, rainfall and temperature. The worm cycle is most active under cool and wet conditions leading to rapid build up of worm burdens in the stomachs and guts of grazing animals. It can almost stop when it is hot and dry.

 

Worm cycle:

  • Eggs produced by the parasite are shed in the faeces of the animal onto the pasture.
  • Out of these eggs hatch larvae which attach to grass and herbage.
  • Larvae are then ingested by the grazing host.


 


Nematode parasites of cattle and sheep

1. Toxocara vitulorum

A round worm with a very specific life cycle, which does not affect mature cattle.  It occurs in the intestines of suckling calves and is present in most tropical countries. The calves become infected before birth and also via the milk. After ingestion the larvae penetrate the intestinal wall and migrate to other tissues of the host especially to the lungs, via the blood stream. The larvae are coughed up and then re-swallowed to re-enter the intestines, become adult worms in the intestines where they produce eggs. High numbers can lead to stunting of calves.

 

2. Haemonchus contortus

Also called the barber pole worm. It is a very aggressive and common blood-sucking stomach worm of cattle and sheep. It is found all over the world, but is less common or even absent from dry areas. It has a direct life cycle. Infective larvae can survive for several weeks on pasture under wet conditions. After the larvae are ingested by the host, they become adults, attach to the lining of the stomach and start suckling blood. Depending on the numbers of worms present in the stomach this can lead to severe anaemia and even death in young animals. Worms on the lining of the stomach are visible at post-mortem as very fine reddish small threads. They can easily be overlooked if the post mortem is not done carefully.

 

 

3. Trichostrongylus species

There are several species of this worm widely spread in the tropics. The worm is brownish, pinkish in colour and is found in the stomach and small intestine of cattle, sheep and goats. They thrive on nutrients absorbed from the contents of the gut.
 
Trichostrongylus tenuis are small hair like nematodes usually less than 7 mm long and difficult to see with the naked eye.
(c) Dr. John W. McGarry and the School of Vet Science in Liverpool

 


 

4. Cooperia species

These are small, red coloured worms found in the small intestine of most ruminant animals. They have a direct life cycle similar to Trichostrongylus.


5. Ostertagia species

They are mainly found in the stomach and occasionally in the small intestine of livestock. They have a direct life cycle and are able to survive longer outside the host even under harsh conditions. They normally infect pasture during the onset of the long rains.


6. Nematodirus species

They are found in the small intestine of livestock. The eggs can survive harsh environmental conditions on the pasture. When environmental conditions improve (rainy and wet) the larvae hatch and the pasture all of a sudden becomes infectious for grazing animals.


7. Chabertia species

They are also known as the large mouthed bowel worms. They are found in the large intestine of most ruminants. The larvae penetrate and embed in the wall of the intestine.

The signs of round worm infection are shared by many diseases and conditions, but based on certain symptoms, grazing history, and season, a presumptive diagnosis can be made.

 

  • Young animals are most often affected, but adults not previously exposed to infestation frequently show signs and succumb. Animals in a state of poor nutrition are more susceptible than animals in good condition. 
  • Ostertagia and Trichostrongylus infestations lead to profuse watery diarrhoea which is usually persistent.
  • Haemonchus causes constipation and variable degrees of anaemia. - In sheep infected by large numbers of Haemonchus the conjunctiva (the mucous membrane that lines the inner surface of the eyelid and the exposed surface of the eyeball) can be snow white in colour.
  • Heavy worm infestation results in progressive weight loss, weakness, a rough coat, loss of appetite, and oedema, particularly under the lower jaw - a condition termed as bottle jaw. 
  • Toxocara can cause in rapid breathing and coughing in young calves.

 

Note that egg counts are not always an accurate indicator of the number of adult worms present as egg laying is not always constant; some species of worms lay more or less eggs than others, and  immature worms and larvae are not egg layers.

Some worms are much more aggressive than others. For example 100 Haemonchus worms in a lamb do as much damage as 5,000- 10,000 Ostertagia worms.

 

Post mortem findings and Diagnosis

Adult worms are usually visible to the naked eye. Some are more easily seen than others. Worms may be only visible due to their movement in fluid stomach and intestinal contents.

 

  • The mucus membranes are often pale.
  • The carcass may be emaciated, but in some instances where an animal has been overwhelmed by a sudden massive invasion of larvae the carcass may be in good condition.
  • The abomasum is frequently fluid filled and this may exend into the small intestine, especially in Haemonchus infestations.
  • The liver is pale and fragile
  • The alimentary tract will reveal worms when opened. Check especially the stomach, and the large intestine.


 

Prevention - Control - Treatment

 

Round worm infestation can be controlled through adherence to the following measures:

 

  • In young cattle round worm infection can be controlled by the use of broadspectrum anthelmintics (drugs to expel worms) in conjunction with pasture management to limit reinfestation.
  • Pasture management includes a move to clean pastures e.g. grass conservation areas or hay aftermath, or alternate grazing with other host species, or integrated rotational grazing in which susceptible calves are followed by immune adults.
  • A special strategic treatment is required in sheep to counter the low immunity seen in ewes around lambing time. Treatment within the month before and the month after lambing should be given. Supportive management after treatment includes movement of sheep from contaminated pastures to cattle pastures, grass conservation areas, or pastures not grazed by sheep for several months. This period may vary from several weeks to several months depending on the weather pattern (longer if wet and cool, shorter if dry and hot).
  • Resting pasture for more than 10 weeks will reduce the number of infective larvae on pasture. Separating young and mature animals in grazing paddocks or grazing different species of animals together. These practices will help to reduce parasite mass and reduce infestation levels.
  • Better grazing management should avoid overstocking of animals on a particular paddock. Grazing management should also ensure that there are alternative grazing areas, should avoid damp grazing areas and always ensure that animals are in good condition. Well nourished animals are less likely to acquire heavy worm infestations.

 

Treatment

The following treatments and drugs are recommended for round worms.

  • Albendazole should be administered orally at the end of the cold season and beginning of the dry season. The drug should be given at the rate of 10 mg/kg body weight
  • Fenbendazole should be given at the end of the cold and beginning the dry season by mouth at the rate of 8 mg/kg body weight
  • Ivermectin can be used in different forms such as injection, orally, or as a pour on. Should be given at the rate of between 0.2 - 0.5 mg/kg body weight as a subcutaneous injection. Giving anthelmintics by injection is recommended as it avoids the risk of damage to the animal's throat through rough drenching and none of the drug is lost.
  • Levamisole and oxyclazanide in combination should be given by mouth at 0.25 ml/kg body weight
  • Albizidal antihelmintica as a botanical treatment- the leaves of the tree are fermented and sieved and administered orally.

NB. Always follow the manufacturer's recommendations when administering drugs.

 



Common traditional practices

 

Though traditional wormcure is practiced widely, reports have also been shared where traditional treatment has killed the animals under treatment. Dosage is very difficult as active content of plants vary depending on season and stage of growth. It is safer to use the commercial products with known dosis rate. If this is not available seek advice from the local herbalist.
  • Luo (cattle, goats, sheep): Cut about 2kg of fresh awayo (Rhus vulgaris) roots, put in 1 kg of water and leave overnight. Sieve and drench with 0.5 litre once a day for a week. Give half this dose for calves, goats and sheep. Give when it is cool and after the animal has eaten. 
  • Embu / Gikuyu (cattle, goats, sheep): Collect 2 handfuls of dry seeds of mugaita (Rapanea melanophloeos). Crush and mix with 1 litre of water. Boil gently for 20 minutes. Allow to cool, then drench once. For goats, sheep and calves use 500 ml; for large animals use 1 litre. Drenching should be done in the evening when it is cool. Repeat after 2 weeks. 
  • Kipsigis (cattle, goats, sheep): Crush 0.25 kg of matakarek (Rapanea melanophloeos) and mix in 1 litre of water. Let boil for 15 minutes. Allow to cool then drench the whole amount once. For small animals use 500ml; for large animals use 1 litre. Repeat after 3 weeks. 
  • Samburu (camels, cattle, goats, sheep): In the rainy season drive animals to areas with salty soils when the water has dried up. The animals will lick the salt from the surface of the ground. 
  • Maragoli (cattle, goats, sheep): Chop 2 bulbs of saumu (Allium sativum) and mix with 4 litres of water. Drench with 0.5 litres twice in 1 day. This treats worms and liverflukes. The dose is the same for adult cattle, sheep and goats. 
  • Somalia Ethiopia: Grind 2 fruits of Gosso (Hagenia abyssinica) in 0.5 of water . Drench a sick cow with this before it goes to pasture. Use half the amount for goats and sheep.

Review process:

1. William Ayako, KARI Naivasha. Aug - Dec 2009
2. Hugh Cran , Practicing Veterinarian Nakuru. March - Oct 2010 
3. Review workshop team. Nov 2 - 5, 2010 
 

  • For Infonet: Anne, Dr Hugh Cran
  • For KARI: Dr Mario Younan KARI/KASAL, William Ayako - Animal scientist, KARI Naivasha
  • For DVS: Dr Josphat Muema - Dvo Isiolo, Dr Charity Nguyo - Kabete Extension Division, Mr Patrick Muthui - Senior Livestock Health Assistant Isiolo, Ms Emmah Njeri Njoroge - Senior Livestock Health Assistant Machakos 
  • Pastoralists: Dr Ezra Saitoti Kotonto - Private practitioner, Abdi Gollo H.O.D. Segera Ranch
  • Farmers: Benson Chege Kuria and Francis Maina Gilgil and John Mutisya Machakos 
  • Language and format: Carol Gachiengo

Information Source Links

  • Barber, J., Wood, D.J. (1976) Livestock management for East Africa: Edwar Arnold (Publishers) Ltd 25 Hill Street London WIX 8LL
  • Blood, D.C., Radostits, O.M. and Henderson, J.A. (1983) Veterinary Medicine - A textbook of the Diseases of Cattle, Sheep, Goats and Horses. Sixth Edition - Bailliere Tindall London. ISBN: 0702012866
  • Blowey, R.W. (1986). A Veterinary book for dairy farmers: Farming press limited Wharfedale road, Ipswich, Suffolk IPI 4LG
  • Force, B. (1999). Where there is no Vet. CTA, Wageningen, The Netherlands. ISBN 978-0333-58899-4
  • Hall, H.T.B. (1985). Diseases and parasites of Livestock in the tropics. Second Edition. Longman Group UK. ISBN 0582775140
  • Handbook on Animal Diseases in the Tropics 4th Edition Sewell & Brocklesby
  • Hunter, A. (1996). Animal health: General principles. Volume 1 (Tropical Agriculturalist) - Macmillan Education Press. ISBN: 0333612027
  • Hunter, A. (1996). Animal health: Specific Diseases. Volume 2 (Tropical Agriculturalist) - Macmillan Education Press. ISBN:0-333-57360-9
  • ITDG and IIRR (1996). Ethnoveterinary medicine in Kenya: A field manual of traditional animal health care practices. Intermediate Technology Development Group and International Institute of Rural Reconstruction, Nairobi, Kenya. ISBN 9966-9606-2-7.
  • Merck Veterinary Manual 9th Edition
  • Pagot, J. (1992). Animal Production in the Tropics and Subtropics. MacMillan Education Limited London
  • The Organic Farmer magazine No. 50 July 2009 
  • The Organic Farmer magazine No. 51 August 2009
Last updated on:
Mon, 10/30/2017 - 20:00
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