Table 3.

The effect of environmental variables on the survival of M. bovis

Conditions	Exposure	Survival	Detection by	Ref.
Temperature
Mixed with faeces in open air (Berks)	Winter from November	⩾5 months	Guinea pig infectivity	[176]
	Autumn from September	4 months
	Summer from June	<2 months
Mixed with faeces or soil (Berks)	Summer from June or May	5 months		[300, 301]
Absorbed onto cotton ribbon (New Zealand)	Winter and spring	>14, <28 days		[177]
	Summer	<7 days
In the laboratory	0 °C	50% at 36 days	Culture	[302]
	16 °C	50% for <1 day
In soil, water, hay or maize (Michigan, USA)	Autumn and winter	30 ± 13 (s.d.) days	Culture	[178]
	Winter and spring	29 ± 26 days
	Spring and summer	6·9 ± 12·5 days
In possum carcasses on pasture (New Zealand)	Winter	20–27 days		[181]
	Summer	<3 days
Moisture
In the laboratory	100% relative humidity	50% at 43 days	Culture	[302]
	57% relative humidity	50% at 8 days
	5% relative humidity	50% for <1 day
In faeces, dry soil and moist soil in Tropical Australia	Shaded conditions	Favourable for survival		[179]
Ultraviolet radiation (including solar radiation)
Mixed with faeces in open air (Berks) (September)	Exposed	4 months	Guinea pig infectivity	[176]
	Shaded and sheltered from rain	6 months
In the laboratory	UVA radiation (375 nm)	80% for 20 min	Culture	[302]