Page 525 - The Veterinary Laboratory and Field Manual 3rd Edition

462 Regula Waeckerlin and Susan C. Cork

The principal climatic factors driving mosquito propylene glycol and storage at 4°C will usually
distribution are temperature and precipitation. still be sufficient for DNA/RNA detection by
Baited trapping can be performed from dura- PCR, depending on the storage duration and the
tions of a 12 h trap night to one week or more. stability of the virus to be detected.
The method of trapping used depends on the
questions to be answered and the resources
available (Figure 14.1). Collection can be made ticks
dry, in ethanol, propylene glycol or formalin
depending on the future use. Dry, cool condi- Ticks are important vectors of Protozoa,
tions for mosquito storage are preferred for Spirochaeta, viruses and other pathogens. Table
virological work and determination of species 14.2 gives an overview of the most important
composition. However, if cool storage conditions tick-borne diseases, the geographic location,
cannot be maintained, moulding of the samples the species that transmit them and important
may be a problem. Collection in ethanol and diagnostic techniques.

Table 14.2 Important tick-borne pathogens.

Pathogen Tick species distribution Vertebrate hosts diagnostic methods
Intracellular
bacteria
rickettsia
Rickettsia Dermacentor North America Three hosts Blood / buffy coat /
rickettsii variabilis (mostly east) Small mammals CSF smear (Giemsa,
Central America (larvae, nymphs) Wright, Dif-Quick stain)
Dogs, cattle, horses, IF, IHC from lesion
humans (adults) PCR
Serology (IFA, ELISA)
Rickettsia Dermacentor North America Three hosts
rickettsii andersoni (west) Small mammals
(larvae, nymph)
Large mammals
(adults)
Rickettsia conorii Dermacentor Europe Three hosts
reticulatus Central Asia Small rodents (larvae,
(west) nymph)
Deer, dogs (adults)
Rickettsia conorii Dermacentor Europe Three hosts
Rickettsia slovaca marginatus Small rodents (larvae,
nymph)
Large herbivores,
carnivores (adults)
Boutonneuse Rhipicephalus worldwide Three hosts
fever (Rickettsia sanguineus Dog, wild carnivores,
conorii) human (adults)
Rickettsia
rickettsii

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