Comparative and Veterinary Pharmacology

5.2.1 Avermectins and Terrestrial and Aquatic Invertebrates

The avermectins are highly potent insecticides. Exposure to avermectins can elicit a
number of responses, including adult and larval mortality, an effect on feeding,
disruption of water balance, a reduction in growth rate, interference with moulting,
inhibition of metamorphosis and/or pupation, prevention of adult emergence, dis-
ruption of mating and interference with egg production and oviposition (Strong
1993 ; Strong and Brown 1987 ). As a consequence, dung from animals treated with
avermectins may not support the development of either target (e.g.Haemotobia
irritans, Musca autumnnalis, Musca domesticaandMusca vetustissimia) or non-
target (e.g. sphaerocerids, muscids, sepsids and coleopterans) insects (Schmidt
1983 ; Strong and Brown 1987 ; Wall and Strong 1987 ; Ridsdill-Smith 1993 ; Madsen
et al. 1990 ; Sommer et al. 1992 , 1993 ; Strong and James 1993 ). The toxicity of

Table 2Reported subtle effects of pharmaceutical compounds on aquatic and terrestrial organisms
Substance(s) Medicine class Reported effect Reference
Avermectins Parasiticide Adult insects – loss of water balance,
disruption of feeding and reduced
fat accumulation, delayed
ovarian development, decreased
fecundity and impaired mating.
Juvenile insects – delayed
development, reduced growth
rates, development of physical
abnormalities, impairment of
pupariation or emergence and a
loss of developmental symmetry

Floate et al. ( 2005 )

Tetracyclines,
macrolides
and
streptomycin

Antibacterials Antibacterial resistance measured in

soil bacteria obtained from sites

treated with pig slurry

Sengelov et al.

( 2003 )

Cypermethrin Ectoparasiticide Impact on dung decomposition Sommer and Bibby
( 2002 )
Fenbendazole Parasiticide Impact on dung decomposition Sommer and Bibby
( 2002 )
Tylosin Antibacterial Impacts on the structure of soil
microbial communities

Westergaard et al.
( 2001 )
Erythromycin Antibacterial Inhibition of growth of aquatic plants Pomati et al. ( 2004 )
Tetracycline Antibacterial Inhibition of growth of aquatic plants Pomati et al. ( 2004 )
Diclofenac (used
as veterinary
product in
Asia)

NSAID Inihibition of basalaEROD activity

in cultures of rainbow trout

hepatocytes; effects on vulture

populations

Laville et al. ( 2004 )

Sulfamethazole Antibacterial Inhibition of basal EROD activity in
cultures of rainbow trout
hepatocytes

Laville et al. ( 2004 )

Sulfadiazine Antibacterial Inhibition of degradation of human
pharmaceuticals in soils press)

Monteiro and Boxall
( 2009 )
a7-ethoxyresorufin-o-deethylase

Veterinary Medicines and the Environment 305