HOW TO SUBMIT SAMPLES FOR ISOLATING PULMONARY MYCOPLASMAS IN SMALL RUMINANTS
In order to isolate Mycoplasmas, we require a pulmonary specimen in good conditions. It would also be possible to use fresh nasal swabs, followed by direct analysis, to isolate Mycoplasmas, Acholeplasmas and Ureaplasmas — these being saprophytic flora not necessary implicated in pneumonic processes. In any case, the swabs must contain transport medium to secure preservation of the Mycoplasmas. It is not acceptable to ship the swabs without preservation medium, since drying would cause the death of the microorganism.
- Select animals that have died recently or which you have sacrificed.
- Drain the lung tissue (which easily decomposes) to avoid contamination during transport.
- Ship the lung whole or in large pieces.
- Cool before sending in a polyspan box. Do not freeze.
- In addition to the lung tissue, submit joint fluid or other organs that appear damaged in young ovine or caprine cattle.
From the lung tissue thus submitted, we can isolate Pasteurella and Mycoplasmas and manufacture a corresponding mixed autovaccine.
HOW TO PREPARE AN AUTOVACCINE AGAINST MYCOPLASMAS
The electron microscopic image shows the capsule of a Mycoplasma. As you know, our formulations include capsular antigen within the liposomes. A similar procedure is followed in the case of Mycoplasmas. The first autovaccines have been in operation for a number of months, with excellent results — though it is still too early to draw firm conclusions.
For the time being, no company or research laboratory is using this vaccinal technology with Mycoplasmas. Exopol is currently applying the technique with M. agalactiae, M. bovis and M. hyopneumoniae.
MYCOPLASMAS IN SMALL RUMINANTS
The clinical picture of mycoplasmosis normally lacks pathognomonic characteristics, and the symptoms observed can also be found or can mimic those seen in other clinically important infections. Consequently, the diagnosis of Mycoplasma infection can easily be mistakenly interpreted by the veterinarian. For example, in acute processes involving Mycoplasma capricolum or M. mycoides spp. mycoides, the animal can die suddenly without any warning signs. In such cases the histological changes are minimal, and many routinely diagnosed cases without the suspicion of Mycoplasma infection can easily be classified as corresponding to an indeterminate etiology.
Many species of Mycoplasma have been isolated from goats and sheep. Some strains have only been isolated once or a few times, and their role in disease (if any) is completely unknown at the present time. This circular includes an updated list of the different types of Mycoplasma isolated from sheep and goats, and provides a brief description of their pathology and possible causal role in the disease.
Mycoplasmas causing agalactia
This important Mycoplasma causes disease in goats and sheep, and is isolated mainly in Mediterranean regions.
The term contagious agalactia of sheep and goats suggests that only the females are affected when in fact both sexes are susceptible, and moreover other Mycoplasmas are also able to cause agalactia (M. capricolum, M. mycoides spp. capri, M. mycoides spp. mycoides, and M. putrefaciens).
The disease produced by M. agalactiae is of considerable economic importance, due to its high morbidity rather than to the associated mortality. The disease may be unapparent, mild, acute or chronic. Affected females show malaise, fever and mastitis that leads to a decrease in milk production and to agalactia. A large number of germs appear in the milk as well as in the blood for a brief period of time. In this way the Mycoplasmas migrate towards other organs, occasionally causing severe keratoconjunctivitis and arthritis that can affect one or more joints (polyarthritis). However, we often only observe subclinical mastitis, with symptoms other than a positive California test. Although experimental evidence is lacking, the infection seems to be transmitted through the colostrum or milk containing the microorganism. Females are easily infected as a result of the introduction of a few germs in the teat canal, or as a consequence of scantly hygienic practices in the milking room, or during manual milking. In the same way, infections may result due to M. capricolum, M. mycoides spp. mycoides and M. putrefaciens. In any case, it should be taken into account that the clinical symptoms frequently appear in non-lactating animals; other infectious routes must therefore also be considered. There is likewise no evidence to suggest infection in drinking areas, common pastures, etc., though experience tells us that infection does occur in such places.
M. agalactiae has also been associated with cases of granular vulvovaginitis in goats. Pulmonary lesions are not frequent, but have nevertheless been reported.
Mycoplasma mycoides spp. capri
This Mycoplasma was considered the etiologic agent of caprine contagious pleuropneumonia. Although it is regarded as rare, it is serologically related to M. mycoides spp. mycoides — thus leading to diagnostic errors.
Mycoplasma mycoides spp. capri has also been isolated from natural cases of caprine mastitis. In one experimental study, inoculation of the organism into the teat canal initially induced a decrease in milk output, resulting in agalactia. As in the case of infections produced by M. putrefaciens, the organism does not spread to the contralateral gland.
Mycoplasma mycoides spp. mycoides
Mycoplasma m. spp. mycoides is best known as the cause of bovine contagious pleuropneumonia — a highly destructive disease in bovine cattle that has been eradicated in Spain. However, Mycoplasmas of caprine origin and serologically indistinguishable from the bovine form of Mycoplasma mycoides spp. mycoides have been known to cause severe disease in goats.
The difficulties found in differentiating certain Mycoplasma species has led to the definition of a so-called "mycoides" group. Two of the species implicated in agalactia syndrome (M. mycoides spp. mycoides LC and M. capricolum), as well as M. mycoides ssp. mycoides SC and M. mycoides ssp. capri, the serogroup F38 and serogroup 7 (bovine) belong to this group of pathogens.
M. mycoides spp. mycoides LC has been isolated from goats and sheep with mastitis, arthritis or polyarthritis, conjunctivitis, lymphadenitis, peritonitis, pericarditis, septicemia, some forms of pneumonia (interstitial, fibrinous), and pyrexia.
As its name suggests, this Mycoplasma induces an intense odor of putrefaction. In 1980, this Mycoplasma was identified as a cause of caprine mastitis leading to agalactia. There are often no clinical signs other than mastitis and agalactia. The pathogen causes no fever, and the mastitis does not spread to the other udder.
Lactating animals inoculated via the oral, intranasal or intramuscular route experimentally do not develop septicemia or other clinical symptoms.
Mycoplasmas causing arthritis
Mycoplasma capricolum is primarily a pathogen of goats, though it has also been found in sheep and cows. In goats, M. capricolum is highly destructive, causing important mortality and morbidity. The primary clinical manifestation is severe arthritis (polyarthritis). Mycoplasma capricolum causes acute conditions when administered parenterally or even orally. The organism progresses in the form of septicemia, with severe involvement of the joints — leading to permanent lameness. In young goats it also produces fever, though the latter may be of short duration and even asymptomatic in adults.
In an experimental study, the young goats acquired the infection as a result of the ingestion of 100,000 germs. Septicemia appeared 24 hours after oral exposure, and the blood was in all cases positive for M. capricolum five days after inoculation. These animals presented pneumonia and meningitis, in addition to the characteristic joint problems. Experimentally, mastitis is also produced, though the latter is less commonly observed in the natural infection.
Mycoplasmas causing conjunctivitis
Mycoplasma conjunctivae causes conjunctivitis and keratoconjunctivitis in goats and sheep, and can frequently be isolated from the eyes and nasopharynx. The infected animals present lacrimation, conjunctival injection (hyperemia), iritis and keratitis, and total blindness may result.
The disease is usually mild, however, lasting for about one week or, in more severe cases, one month. The animals can recover without treatment.
Mycoplasmas causing pneumonia
Mycoplasma ovipneumoniae plays an important role in disease among goats and sheep. This Mycoplasma can often be isolated from the lungs, trachea and nasal cavities, and occasionally from the eyes of sheep with pneumonia — though it is also found in the respiratory tract of healthy sheep. The intravenous inoculation of sheep and of one-day-old lambs via aerosol leads to the development of interstitial pneumonia.
The natural disease caused by M. ovipneumoniae has often been described. Some studies have suggested the existence of synergic action with Pasteurella multocida and/or haemolytica in the production of chronic pneumonias that mainly affect animals under one year of age. Mortality rarely exceeds 10% under experimental conditions, though the economic losses are considerable due to the delayed livestock growth and the elimination of animals that otherwise would be destined for keeping.
This Mycoplasma is isolated in goats and sheep, although the organism is sometimes not regarded as a pathogen. In an experimental study, M. arginini did not induce mastitis in goats, yet it persisted at high concentrations in the udders of sheep for at least 9 days, causing neutrophilia without alterations in the consistency and/or appearance of the milk.
Mycoplasma arginini has been isolated from cases of ovine keratoconjunctivitis and has often been described in pneumonic processes in sheep.
Infrequent or erratic Mycoplasmas
This Mycoplasma can occasionally be isolated from the lungs of goats. Due to the great antigenic and structural similarity between M. agalactiae and M. bovis, the latter have only recently been defined as independent species. This great similarity between the two microorganisms could in theory facilitate the adaptation of strains of M. bovis to small ruminants when exposed to high doses of the germs. M. bovis is often associated with bovine mastitis, and in view of its high incidence (at least 10-20% of all farms in Spain are infected), it is important to ensure its absence when administering bovine colostrum to small ruminants, or on using bovine milk as a nutritional supplement in nursing animals.
In experimentally induced infections in goats, the microorganism produced fever, with swelling of the glands and alteration of the milk (with clots and serous secretions).
This species has only been isolated once in sheep and goats.
Mycoplasma gallinarum has been isolated at least once in sheep and goats. The importance of such isolation is not clear, however, because the Mycoplasma may have been acquired via contamination from avian species (for example, through the consumption of bedding as a source on non-protein nitrogen).
Serotype 5. Isolated from the hoof of a goat.
Serotype 7. Isolated from the lung tissue of a goat.
Serotype 11. Isolated from vagina in Australian sheep.
Serotype 16. Mycoplasma spp. F38 is now considered to be the etiologic agent of caprine pleuropneumonia (not seen in Spain), with a very high mortality.
Serotype 17. Isolated from the ears of goats in Australia.
Serotype 19. Isolated from the ears of goats in Australia.
Serotype 20. Isolated from the ears of goats in Australia.
Acholeplasma axantham. Without pathological significance.
Acholeplasma granularum. Without pathological significance.
Acholeplasma laidlawii. Without pathological significance.
Acholeplasma oculi. These Mycoplasmas have been isolated in cases of conjunctivitis or keratoconjunctivitis in goats and sheep.
The Ureaplasmas have been isolated in goats and sheep. There is a general lack of information on these microorganisms, however.