Borrelia

Longer, wider, helical spirochaetes with a linear chromosome and linear and circular plasmids
Obligate parasites transmitted by arthropod vectors
Cause systemic infections in many animals and humans
Slow growth in specialised culture media

Caused by Borrelia anserina
Acute, endemic disease of birds in tropical and subtropical regions
Chickens, turkeys, pheasants, ducks and geese susceptible
Transmitted by soft ticks of the Argas family, but also via contact with infected material such as blood and tissues
Transmitted transovarially and trans-stadially via the tick population
Outbreaks during peak tick activity during warm, humid conditions
Fever, anaemia and wight loss occurs, with development of paralysis later
Immunity is serotype specific
Diagnosis using dark-field microscopy of buffy coat smears or immunodluorescence of blood or tissues
Giemsa-stained smears and silver impregnation of tissues
Isolation of borreliae by inoculation of embryonated eggs or chicks
Antibiotic treatment
Inactivated vaccines available