Table 1.

First evidence related to the ability of melatonin to protect against viral infections

Virus	Animals	Doses of melatonin	Effects	Ref.
EMCV	25 female 2‐3‐months‐old BALB/cj mice	1 µg i.p./mouse daily for 10 days	Prevention of paralysis and death of infected mice	32
SFV	18 Charles River outbred ICR female mice (CD1)	500 µg/kg s.c. daily, 3 days before until 10 days after virus inoculation	Reduction of the death rate	33
			Delay of the onset of the disease
	10 Charles River outbred ICR female mice (CD1)	500 µg/kg s.c. daily, 3 days before until 10 days after virus inoculation	Decrease the virus load in blood	33
WN‐25*	16 Charles River outbred ICR female mice (CD1)	5 µg/mouse s.c. daily, 2 days before until 8 days after virus inoculation	Counteracts the immunodepressive effect of stress exposure	33
			Prevention of the stress‐related encephalitis
			Prevention of the death of infected mice
VEEV	25 male albino mice (NMRI‐ IVIC strain)/group	250–500 µg–1 mg/kg s.c. daily, 3 days before until 10 days after inoculation	Reduction of mortality rates	34
			Delay of the onset of the disease
			Deferring of the time to death
	6 male albino mice (NMRI‐ IVIC strain)	500 µg/kg s.c. daily, 3 days before until 10 days after inoculation	Decrease the virus load in brain Decrease the virus load in serum	34
	3 male albino mice (NMRI‐ IVIC strain)/group	250–500 µg/kg s.c. daily, 3 days before until 10 days after inoculation	Increase the VEEV‐mediated IgM antibody titres	34
AMDV	90 wild type (demi‐buff or demi strain) minks 6000 male and female demi strain minks 3000 male and female demi and mahogany strains of kit minks	Silastic implants (0.65 cm length, 0.21 cm diameter) containing 2.7 mg melatonin crystals homogeneously suspended in medical grade silastic polymer	Reduction of mortality rates	35

EMCV, encephalomyocarditis virus; SFV, Semliki Forest virus; VEEV, Venezuelan equine encephalomyelitis virus; AMDV, Aleutian mink disease virus; i.p., intraperitoneal; s.c., subcutaneal.

^*an atenuated West Nile virus strain