Mallein test

The mallein test is a sensitive and specific clinical test for glanders, a common bacterial disease of equids (horses, donkeys, mules).^[1] This test is an allergic hypersensitivity test used as a diagnosis for glanders.^[2] It is caused by a bacterium called Burkholderia mallei, which is contagious for humans and other species.^[3] The occurrence of glanders must be reported to the World Organisation for Animal Health.^[4] Mallein, a protein fraction of B. mallei, is usually injected by an eye-drop. If an animal is infected, the animal will show swelling in the eye from around 48 hours of injection and may be accompanied by secretion and conjunctivitis.^[5] Mallein is non toxic to normal animals.^[6]

History

Mallein was discovered in 1890.^[7] Before 1934, glanders was widespread.^[8] In the early 1900s, glanders was common in Europe, the United States of America, and Canada, and has been successfully eliminated by mass testing and the slaughter and destruction of campaigns.^[9] Glanders is still present in Asia, the Middle East and South America^[10]

Limitations and benefits

Limitations

Although Mallein is the most commonly used form of testing for glanders, cross reactions were reported between Burkholderia mallei and Streptococcus equi,^[11] which is a bacteria-caused contagious upper respiratory tract infection of equines.^[12] This resulted in false-positive reactions.^[13]

Benefits

The specificity of Mallein tests and the efficiency and potency of it are connected to the "molecular weight of protein fractions, antigenic range, and virulence".^[14]

Test procedures and methods

• Preparation of crude mallein^[15]
• Purification of malleo proteins^[16]
• Trichloroacetic acid (TCA) preparation^[17]
• Ammonium sulfate precipitation^[18]
• Gel filtration chromatography^[19]
• Sensitization of animals^[20]
• Potency test^[21]
• Intradermopalpebral^[22]

See also

Burkholderia mallei
Glanders

References