External parasites are one of the most important problems in swine farms due to the economic losses they generate. It is important to know aspects of their epidemiology and main characteristics to implement prevention measures in swine farms. Here we will review the main external parasites affecting the pig industry.

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Swine lice

Scientific name: Haematopinus suis

The swine lice are distributed throughout the world. It is mainly transmitted by contact between pigs, especially in high-density production and poor hygienic conditions. There is also significant transmission from sow who have the lice to their piglets.

The swine lice are usually located in the neck and jaw region, axillary and inguinal area due to body temperature. It is also located in the back and ear area because it is difficult for the pig to access. In cases of high infestation, the lice can be all over the body.

Impact on health and production

Pigs with lice infestation show a considerable reduction in daily weight gain. In addition, swine lice promote the development of other diseases. The swine lice are considered a vector of African Swine Fever, Eperythrozoon suis, and swine influenza virus.

When this swine lice causes a severe infestation in animals, it can cause anemia. This reduction of the blood component is serious because it affects body processes in general.

Furthermore, it is considered that the greatest economic impact of these external parasites is the damage generated in the skin. The swine lice generate itching and the pig scratches these areas, generating lesions. These lesions can reduce the quality and value of the meat.

In piglets infested by swine lice, growth retardation is observed.

How are swine lice diagnosed?

Diagnosis of swine lice is made visually in the areas preferred by the parasite. Adult lice are easily observed and can be removed manually. Diagnosis is made by observation under a microscope.

How to treat and control swine lice?

Avermectins or organophosphates are used to treat swine lice. These are administered as a single pour-on application. Amitraz or deltamethrin can also be used against these external parasites. It is important to reach the diagnosis to treat all affected populations.

On the other hand, prevention is based on the use of insecticides. The main insecticides used against swine lice are macrocyclic lactones. The aim is to treat pregnant sows or boars to avoid the transmission of these external parasites to the piglets.

Swine mite

Scientific name: Sarcoptes scabiei

Sarcoptes scabiei is distributed throughout the world. These external parasites are zoonotic; they are transmitted from pigs to humans or vice versa. Swine mite transmission is by close contact, where larvae are transmitted. The affected animals can be all adults or piglets infested by contact with the sow at birth.

On the other hand, the swine mite can survive for two to three weeks in the environment. This explains the infestation in pigs indirectly, by contact with surfaces where the parasite is present.

The pig mite’s favorite site is near the ears. From this area, scabies spread throughout the body, mainly to the back, flanks, and abdominal area.

Effects on health and production

These external parasites, swine mite, are characterized by penetrating the skin and digging tunnels through it. This type of parasitism is called scabies. Swine mite generates pruritus, hair loss, and severe erythema in the animal. If the infestation is aggressive, it can become contaminated with environmental bacteria and the skin will have an exudate. In general, the pig may show loss of appetite, decreased daily weight gain, weakness, and depression.

How is swine mite diagnosed?

Swine mite diagnosis is made by direct inspection. Emphasis should be placed on observing the ear area as it is the most frequently affected area. Animals affected by the swine mite usually have intense itching. Usually, a whole age group is affected. To confirm the diagnosis, a scraping of the affected areas should be done to see the swine mite under the microscope.

How to prevent swine mite?

The treatment of swine mange can be done with amitraz, macrocyclic lactones, or organophosphates. The withdrawal time of the drugs should always be checked to avoid their residuals in the meat.

Swine mite control focuses on treating sows, which are the main reservoir of the parasite. Boars can also be treated every six months. It is useful to quarantine new pigs for service to rule out the presence of scabies.

Pigs that are infested with mites can be treated with the products mentioned above by spraying. Application of the product can be done on sows 3 to 7 days before farrowing to avoid transmitting the swine mite to piglets.

CONCLUSIONS

External parasites are arthropods that can generate significant economic losses if they infest a pig population. Swine lice and swine mite are the main parasites that are located on the skin and cause serious effects in various areas. In addition, if infestations by external parasites are severe, they will generate a considerable economic loss. Periodic inspection should be carried out to diagnose these parasites and implement control and prevention measures in swine farms.