Mastitis (Mammitis)

Mastitis (Mammitis) is also called inflammation de la ubre.

Mastitis (Mammitis) is an inflammation of the mammary gland. In which the milk undergo physical, chemical and microbiological changes where as mammary glandular tissue under go physical and pathological changes.

In which infected milk colour, consistency change and contains more amount of leucocytes.

Etiology

Mastitis (Mammitis) is caused majorly by Staphylococcus, Streptococcus and coliform bacteria and less importantly by other organism such as other bacteria, viruses, and fungus.

Epidemiology

Prevalence of infection

Mastitis due to staphylococcus, streptococcus infection is more prevalent in India.
Mastitis is prevailing in dairy animals.
Greater risk occurs in 10-12% of individuals herds.
Clinical mastitis increases with increasing parity.

Economic impact

It is one of the most economically important disease of dairy cows.
The economic loss occurs due to reduction in milk, changes in quality milk and milk products.
In addition, disqualification of dairy cow due to chronic mastitis.

Predisposing factors

Stages of lactation
Milking condition
Genetic factors
Poor hygiene
Hybrid animals

Source of infection

S. agalactiae and S. aureus resides primarily in the udder of infected cows.
Exposure to uninfected quarters is limited to milking process.
Strepoccus uberis, S. dysgalactiae and coliforms are normal inhabitants of the cows environment.

Transmission

Invasion through teat canal pore.
Through milkers hands
Through ingestion of infected material from environment.
Fly biting influences the entry of organism.
Contact occur at any time during the life of the cows including milking time between milking dry period prior to first calving in heifers.

Host affected

Cows, buffaloes, sheep, goats, pigs, horses are highly susceptible for mastitis.
Heavily producing cows are mostly susceptible than less producers.

Pathogenesis

Infection occurs mainly through teat canal pore. The set up of infection occurs in two stages:

Invasion stage
Infective stage

1. Invasive stage

In which, organism enter through teat canal and reaches the mammary tissue.
Streptococci enters the epithelium of the ducts develops inflammation and promotes in turn the development of many folds of granulation tissue under the epithelium and become polypoid swelling.
In the epithelium some of the organisms are destroyed by immune cells, neutrophils and all other remaining organism causes oedema in the interstitial tissues and leads to infiltration in the lymphatics.
The epithelial acini vacuolated and desquamated and forms fibrosis due to accumulation of exudates.
In advance and severe cases of mastitis, secretion through teats ceases.
Udder become hard, indurated due to inflammation of interalveolar tissues and retention of secretion which results in collapse of acini and granulation of tissues followed by filling of interstitial space with large number of lymphocytes.
Finally, udder is small, hard and is called shrunken udder.
There is no regeneration of glandular tissue occurs in severe cases of mastitis.

2. Infective stages

At this stage, bacteria undergo multiplication and causes damage to udder tissues.
In acute cases, infection set up toxaemia and leads to death.
Affected udder is hard, swollen, and painful in surviving animals.
Milk become scanty with blood.
The diffusion of bacterial toxins in to other unaffected quarters leads to infection.
Gangrene develop as the infection progress in to blood vessel and causes thrombosis.
At this time, the udder become cold, and becomes greenish or bluish in color.
Pits on pressure and edema is noticed at the side of the flank.
The accumulation of gas in the affected area produce crackling sound on palpation.
In mild cases, necrotic foci appears and is surrounded by fibrotic tissues.
Granulomatous lesions develops.
Summer mastitis is caused by Corynebacterium pyogenes.
More pus produced in abscess.
Fistula develops and discharges pus to the exterior which leads to necrosis and sloughing.

Clinical signs

Per acute form

Pyrexia, anorexia, respiratory distress, swollen , hot and painful udder.
Cessation od milk production.
Exudate are often blood stained.
Mostly, Staph. aureus, Str. Dysgalactiae, Cory. pyogenes, E. coli, and P. aerugenosa.

Acute form

Swollen udder, changes in quality of milk.
Milk become curd like, yellow, brown fluid with flakes and clots.

Subacute form

No changes in the udder tissue.

Chronic form

Udder is haemorrhagic, and fibrotic.
Swollen and palpable supra mammary lymph node.
Udder is thick, firm, nodular and atrophic, yellowish or white fluid with clots and flakes.

Zoonosis

Mastitis milk is unsuitable for public consumption because many diseases such as tuberculosis, brucellosis, staphylococcal infection, streptococcal sore throat, scarlet fever and gastroenteritis are spread through milk to human beings.

Necropsy Findings

In severely affected dead animals necrotic foci appears which is surrounded by fibrous tissues.
Granulomatous lesion seen.
In summer mastitis, abscess, fistula and discharged pus to the exterior and sloughing leads to loss of quarters are observed.

Diagnosis

Physical examination of the udder.
Tests done for the milk abnormalities:
- Strip cup test
- Bromothymol Blue Test (BTB)
- Bromocresol purple test
- Chloride test
- California mastitis test
- White side test
- Catalase test
- Direct test
Isolation and identification of the organisms.
Cultural examinations.
Biochemical test.
Animal inoculation test.
Serological test.
Miscellaneous tests.
Electrical conductivity test.
Radial immune diffusion test.
Milk antitrypsin assay.

Differential diagnosis

Various types of mastitis should be differentiated to achieve forthcoming treatment:

Staphylococcal mastitis
Coliform mastitis
Summer mastitis
Mycoplsmal mastitis
Nocardial mastitis
Pseudomonas mastitis
Anaerobic mastitis

Treatment

Stripping out the milk from the infected quarters.
Cleaning of infected quarters with normal saline and distilled water.
Infusion of antibiotic therapies immediately after the infection.
Contineuos use for antibiotics as per the antibiogram.
Combination of drugs may be used for better remedy.
The following combination of drugs can be used as based on the stages of mastitis with antibiogram results.
Penicillin and its derivatives ( Streptopenicillin, Oxtetracycline).
Gentamycin, Cloxacillin, Lincomycin, Neomycin, Co-trimoxazole and Enroflaxacin.
Antipyretics and anti-inflammatory drugs can be used as per the requirment.
Antihistamin can be used.
Application of astringents over udder tissues to reduce the swelling.
Intravenous therapy using normal saline or dextrose saline solutions to reduce the toxic level in the blood.
In non responsive cases animal should be dried out.
It is done by infusing 30-60 ml of 3% silver nitrate solution, or 20 ml of 5% copper sulphate.

Prevention

Use of inactivated vaccine containing Str.agalactiae, Str.uberis, Staph.pyogenes, Staph. aureus and E. coli in some countries.
Reduction of time of infection.
Treatment and drying off quarters.
Immediate treatment of affected animals.
Culling of non responding animals.

Control

Control of development of new infection.
Dipping of quarter with disinfectant.
Personal hygiene of the milk man before milking.
Seggregation of infected animals and proper treatment based on the antibiogram.
Routine disposal of the soiled matterials and thorough cleaning of shed using disinfectants.