Clinical management of contagious agalactia in ovines.
Contagious agalactia (CA) is a highly infectious disease of sheep and goats characterized by arthritis, interstitial mastitis resulting in decreased milk production and infectious kerato-conjunctivitis (Aiello and Mays, 1998). It is most often observed in farms following conventional husbandry. Mycoplasma agalactiae is the typical etiological agent of CA in small ruminants. However, a few other Mycoplasma species like M. putrefaciens, M. capricolum sub sp. capricolum and M. mycoides sub sp capri may cause similar clinical and pathological indications (Madanat et al., 2001; De la Fe et al., 2005). This infection will result in substantial economical loss due to drop or complete cessation of milk production and abortion combined with high mortality rate (up to 40-70%) in lambs and kids (Madanatet al., 2001; Corrales et al., 2004). The disease was previously listed in Office International de Epizooites (OIE) list B disease class, but it is currently grouped as a notifiable disease (Antunes et al., 2008).
M. agalactiae is comparatively stable at room temperature and frequently transmitted through oral, respiratory and mammary route. It implies that primary site of predilection is mucosa of respiratory tract, small intestine and alveoli of mammary glands respectively (Srivastava, 1982). Once infection is set up, fever is experienced because of bacteremia. Involvement of connective tissue in mammary gland resulting in initial inflammation which eventually turns in catarrhal or parenchymatous mastitis resulting into atrophy and agalactia (Srivastava, 1982, Jones, 1989).
Animals suffering with mastitis may transmit infection to young ones through colostrum or milk. Painful inflammation of joints with accumulation of synovial fluids will cause arthritis mainly in carpal and tarsal joints. Affections in eye end up in extensive losses of cornea, ultimately causing blindness due to vascularization and kerato-conjunctivitis. Affections of genital organs may also be experienced with occasional abortions or stillbirths in pregnant animals, mainly due to uterine inflammation.
History and Clinical Observation
A sheep farm at Choppadandi in Karimnagar district of Telangana state suffered an unexpected onset of arthritis, polyarthritis, clinical mastitis and death. As reported by the owner, the disease appearance coincided with induction into herd of a normal lactating ewe. Some adult ewes experienced chronic joint problems ('big knees'), blindness, agalactia and mastitis. Out of 350 sheep in flock, 56 (16%) were infected. Twenty five sheep died acutely with clinical signs of arthritis or mastitis in three weeks period. Mastitis, arthritis and ocular disorders (Fig. 1) with varied degrees of intensity were witnessed in flock. The arthritic joints were very hot, painful and enlarged (Fig. 2).
[FIGURE 1 OMITTED]
Materials and Methods
Five dead lactating ewes and two dead old lambs were submitted to Animal Disease Diagnostic Laboratory, Karimnagar for necropsy examination and diagnosis. Blood sample, joint fluid, milk from mastitis affected udders and corneal swabs were collected from ailing animals and were sent to Veterinary Biological Research Institute, Hyderabad, Telangana for confirmatory diagnosis.
Diagnosis and Treatment
The clinically diagnosed contagious agalactia cases were confirmed by PCR analysis for Mycoplasma agalactiae. Ceftriaxone, a third generation cephalosporin was used to treat ailing animals at a dosage of 20 mg/kg/day for 5 days. Tylosin, a macrolide group of anti bacterial was also used 15mg/kg/day for 5 days. In combination with chosen antibiotics, one single dose of Meloxicam (0.5 mg/kg); an oxicam group NSAID were also administered subcutaneously.
Results and Discussion
Madanat et al. (2001) reported that morbidity in contagious agalactia may reach up to 30-60% and mortality can increase up to 40-70% in lambs and kids. In the study, the overall morbidity was 16% (56/350) and mortality was around 35.71% (20/56). Arthritis is a characteristic clinical findings in contagious agalactia but its incidence rate varied in different reported studies. Following therapy of Ceftriaxone together with Meloxicam, joint swelling and pain disappeared and a periarticular thick tissue developed gradually. It was observed that approximately 47% of contagious agalactia affected ewes (17/36) had mastitis and was regarded as a frequent clinical finding in contagious agalactia affected ewes.
[FIGURE 2 OMITTED]
The diagnosis of contagious agalactia infected lactating ewes and does was enlarged mammary lymph nodes to a size up to 3 cm in diameter and watery, greenish in color and clots in milk (Aiello and Mays, 1998; Madanat et al., 2001). As also evident in present study, ocular lesions beginning with conjunctivitis, lacrimation and photophobia can also progress to corneal vascularization and eventually into kerato-conjunctivitis (Aiello and Mays,1998). In the study, ocular lesions were noticed in 23% (13/56) of diseased animals. The ocular lesions in ewes were invariably connected to contagious agalactia lesions, arthritis and mastitis.
Since there is no incidence of mortality on post-treatment, improvement in general body condition as well as return of leukocyte counts, heart rate, respiratory rate and body temperature to normal range, it was believed that treatment protocol was effective. Similarly, severity of mastitis, conjunctivitis, keratoconjunctivitis and arthritis was drastically reduced. The treatment outcome of study was quite comparable to that of Van Bree et al. (1994) and Peterson and Keefe (2004).
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M. Kalyani (1), B. Srilatha (2) and J. Raju (3)
Animal Disease Diagnostic Laboratory
Department of Animal Husbandry
Dist. Karimnagar--505503 (Telangana)
(1.) Assistant Director, ADDL, Karimnagar
(2.) Ph.D. Scholar, Department of Veterinary Gynaecology and Obstetrics and Corresponding author. E-mail: email@example.com
(3.) Ph.D. Scholar, Department of Animal Nutrition
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|Title Annotation:||Clinical Article|
|Author:||Kalyani, M.; Srilatha, B.; Raju, J.|
|Date:||Jul 1, 2015|
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