SARCOPTIC MANGE IN CATTLE

To My Quyen, 

Nguyen Khanh Thuan, Nguyen Phuc Khanh, Nguyen Thanh Lam*

1. Introduction

Mange is a highly contagious skin disease caused by one or a combination of several species of mites. Mites affect both domestic animals and humans, but also wildlife of zoonotic importance. The most common mite species in wild and domestic animals is Sarcoptes scabiei. This parasite is a ubiquitous ectoparasite that infects more than 100 species of mammals worldwide. In humans, it is known to cause considerable morbidity in a number of different countries and epidemics can be caused by contagion from a single case of scabies in crowded living conditions. Sarcoptic mange may lead to considerable economic losses in domestic animals with repercussions for the animal trade. It also has devastating consequences for wild animals, above all in isolated populations a situation that is worsening due to the limitations of available chemotherapy (Desoky, 2015).

2. Aetiology

2.1 Parasitic characteristics

Sarcoptes scabiei is in the arthropod class Arachnida, family Sarcoptidae. The mites burrow into the upper layer of the skin but never below the stratum corneum. The burrows appear as tiny raised serpentine lines that are grayish or skin-colored and can be a centimeter or more in length. Other races of scabies mites may cause infestations in other mammals, such as domestic cats, dogs, pigs, and horses. It should be noted that races of mites found on other animals may cause a self-limited infestation in humans with temporary itching due to dermatitis; however, they do not multiply on the human host (CDC, 2018).

3. Epidemiology

3.1 Susceptible hosts

Although Sarcoptes spp. affecting various domestic species that closely resemble each other, parasitologists debate the idea of a common species with adaptation to various hosts versus separate Sarcoptes spp. for each host species. Regardless, when examined microscopically, the sarcoptic mites from cattle (Sarcoptes scabiei var. bovis) will appear very similar to those found on other species (Peek and Divers, 2018).

3.2 Transmissions

Sarcoptes scabiei (bovis) has a life cycle of 10–17 days and may infest cattle of any age, breed, or sex. Infection takes place by direct contact with infected cattle or with environmental fomites, although survival of the mites in the environment is limited to a few days (Andrews et al., 2008). Transient, superficial sarcoptic mite infestations may occur in humans working with cattle affected with sarcoptic mange.

4. Life cycle

Scabies results from the transmission of mites from an infested patient to an uninfected one after extensive contact. Adult female mites are fertilized by males and then burrow into the stratum granulosum of the skin, laying zero to four eggs per day for up to six weeks before dying. Larvae hatch two to four days after eggs are laid and cut through the skin surface and begin to dig new burrows. Three to four days later, the larvae molt into protonymphs, which two to three days later molt into tritonymphs, from which an adult male or female emerges after a further five to six days. The entire cycle takes about two weeks (Figure 2).

After a period of three to six weeks, sensitization occurs to mite metabolites, resulting in pruritis. Sensitization to mite antigens can be demonstrated a month after following primary infestation, with both humoral and cellular responses evident. Most importantly these patients can transmit scabies during this “incubation period” leading to the recommendation of treating all members in a household with some exceptions. Epidemiologic studies support intrafamilial transmission as being most common following sexual transmission among adults (Currier et al., 2011).

5. Gross lesions   

The common scabies mite may attack any part of the body thickly covered with hair; the first lesions usually occur on the withers, along the back, or around the root of the tail. Mites pierce skin causing the serum to exude. As a lesion increases in size a dry scab forms in the middle surrounded by successive zones of moist crust and reddened skin. Mites are most active at the edge of the scab. Infestations cause loss of weight and failure of young stock to thrive and gain normally, and they may cause death to calve or to range cattle exposed to inclement weather (Patrick, 1914). Caused by Sarcoptes scabiei var. bovis, lesions are typically seen over the head, neck and hindquarters (Figure 3). Note the hair loss and severe thickening of the skin in (Figure 4). The white areas show secondary damage due to rubbing. In severe cases there may be almost total hair loss. The close-up view (Figure 5) shows the dry, scaly appearance of the thickened skin (Blowey and Weaver, 2011).

                   6. Diagnosis

6.1 Microscopic examination

Recovery techniques vary, but the following techniques are successful in recovering the parasite from live or dead hosts, respectively. On the living host, deep skin scrapings are made with a scalpel or similar bladelike tool to the point of oozing blood. Direct microscopic examination of scrapings is often not worth the effort. However, if the scrapings are heated gently, mites become active and more observable. If the host is dead, pieces of mangy skin are removed and placed in a petri dish. Heat from the light source of a stereomicroscope (~1 hour) stimulates mites to migrate from the skin. Failing this, scrapings are put in 10%–20% aqueous potassium hydroxide (KOH) solution. The material may be boiled in 20% KOH for a few minutes or put in a water bath (37° C) for a few hours using 10% KOH, until the material has become digested. Then the material is centrifuged (3 minutes at 3000 rpm) and the supernatant decanted. A few drops of glycerine are added to the sediment, which is then examined microscopically (Bornstein et al., 2001).

6.2 Serodiagnostic tests (ELISA)

Serodiagnostic tests (ELISA) can support the diagnosis. This assay, which demonstrates specific antibodies to S. scabiei, has been developed for dogs and red foxes, pigs, camels, lynx, and domestic cats. This technique is used to verify whether an animal with skin lesions has been infected with S. scabiei or not. It is useful in diagnosing mange in animals with atypical or minute skin lesions and in conducting sero-epidemiological surveys (Bornstein et al., 2001).

7. Treatment

(1) Organophosphorus pour-ons, dips, sprays

(2) Gamma BHC 7.5 percent (not milking cows) 5– 25ml in 6L water

(3) Diazinon 2 percent wash, 28ml in 4.5l water

(4) Phosmet 20 percent pour-on

(5) Permethrin 4 percent pour on

(6) Ivermectin 200–300mg/kg by subcutaneous injection

(7) Amitraz – an 0.025 percent solution in water is applied by spray at 5 to 10 litres per animal to wet the whole body. This should be repeated after an interval of 7 to 10 days in severe cases. Further applications, if necessary, may be made at two-to-three-month intervals. Special precautions apply to operatives using this preparation in respect of the wearing of protective clothing for which reference should be made to the manufacturer’s data sheet. The milk with holding time for milking cattle treated with amitraz solution is 48 hours after the last treatment.

(8) In circumstances where the above preparations are not readily available, lime/sulphur dips can be effective. The disadvantage associated with this treatment is that repeat applications at 7-to-10-day intervals may be required on as many as six occasions.

(9) Synthetic pyrethroids. 

These are examples of preparations available. Application routines may vary and response to treatment will determine how many applications may be required. Reference to the appropriate data sheet is essential for information on special precautions and withdrawal times to be observed (Andrews et al., 2008).

8. Control and prevention

As mite eggs take 2–3 weeks to hatch, and as mites can persist in the environment for around 2 weeks, two pour-on organophosphorus treatments, or two subcutaneous injections of ivermectin, 2–3 weeks apart, are needed. Alternative drugs are single doses of doramectin, or eprinomectin, both of which have greater persistence (Blowey and Weaver, 2011).

Certain spray formulations of permethrin are labeled for use against sarcoptic mange mites; however, it is generally not considered the compound of choice. If permethrin is used, the animals should be wet thoroughly with the product and re-treated in 10−14 days.

Practitioners and producers should take care to note whether the compound, dose, and formulation are appropriate for the age of the animal and the production system in use. Eprinomectin and moxidectin pour-on formulations, as well as hot lime sulfur, are approved for use on dairy animals in the US (Ketzis, 2023).

9. References

Andrews, A.H., Blowey, R.W., Boyd, H., Eddy, R.G., 2008. Bovine medicine: diseases and husbandry of cattle. John Wiley & Sons.

Blowey, R., Weaver, A.D., 2011. Color atlas of diseases and disorders of cattle e-book. Elsevier Health Sciences.

Bornstein, S., Mörner, T., Samuel, W.M., 2001. Sarcoptes scabiei and sarcoptic mange. Parasitic diseases of wild mammals, 107-119.

CDC, 2018. Sarcoptes scabiei. Laboratory identification of parasites of public health concern.

Currier, R.W., Walton, S.F., Currie, B.J., 2011. Scabies in animals and humans: history, evolutionary perspectives, and modern clinical management. Annals of the New York Academy of Sciences 1230, E50-E60.

Deak, G., Moroni, B., Boncea, A.M., Rambozzi, L., Rossi, L., Mihalca, A.D., 2021. Case report: successful treatment of sarcoptic mange in European camelids. Frontiers in Veterinary Science 8, 742543.

Desoky, S., 2015. The best methods of control of sarcoptic mange-infested cattle, sheep, and rabbit farms. Basic Research Journal of Agricultural Sciences Review 4, 021-023.

Ketzis, J.K., 2023. Mange in Cattle. MSD Manual. Veterinary Manual.

Patrick, C.D., 1914. Beef Cattle Handbook.

Peek, S.F., Divers, T.J., 2018. Rebhun’s diseases of dairy cattle-E-book. Elsevier Health Sciences.

* Nguyen Thanh Lam, DVM., MSc., PhD

Department of Veterinary Medicine, College of Agriculture, Can Tho University

Address: Campus II, 3/2 street, Ninh Kieu district, Can Tho city, Viet Nam

Phone: +84 (0) 939-468-525

Email: ntlam@ctu.edu.vn