Tick (Ixodes holocyclus) paralysis in the dog--induction of immunity by injection of toxin

Three beagle dogs were immunised against the paralysing effects of holocyclotoxin, using toxic extracts derived from salivary glands of the Australian paralysis tick, Ixodes holocyclus. Upon subsequent challenge with four ED50's of toxin the animals were completely immune, whereas during the early stages 2 of 3 dogs became paralysed after injection with 0.5 ED50. Three immunised beagles, on which 15 I. holocyclus ticks had fed, showed no symptoms but a control beagle became paralysed after 4 I. holocyclus females fed on it. Treatment was instituted immediately upon the onset of clinical signs and the dog recovered uneventfully.

Pyrexia in response to Rhipicephalus appendiculatus infestation in calves

Bos taurus calves free from tick-borne diseases were prophylactically treated with oxytetracycline hydrochloride and phenamidine isothionate 40% (w/v) injections and infested twice with adult Rhipicephalus appendiculatus ticks. Mono- and diphasic temperature rises were observed during primary and secondary exposures respectively with the peak occurring when the ticks were completing engorgement. However, the first rise in the secondary infestation occurred well before repletion and was associated with a hypersensitivity state. The feeding performance, viability and fecundity of female ticks were impaired during the secondary exposure.

Rhipicephalus appendiculatus: cause and vector of diseases in Africa

Rhipicephalus appendiculatus Neum. occurs mainly in the eastern and southern parts of Africa and is the principal cause and vector of some very important stock diseases in these areas. The diseases include the theilerioses, brown tick toxicosis and Nairobi sheep disease. These are briefly discussed, and emphasis is laid on the role of R. appendiculatus in their epidemiology. R. appendiculatus is a 3-host tick particularly well adapted to survive where climate and vegetation are suitable. The basic requirements and breeding potential of this tick are also discussed.

[Fatal neurological syndrome in a collared dove (Streptopelia decaocto) and fixation of ixodes pari (= I. frontalis) tick (author's transl)]

Tick paralysis is probably a common condition in wild birds, but rarely observed. The authors report the case of a collared dove (S. decaocto) presenting a fatal neurological syndrome associated with the fixation of a Ixodes pari female above the right eye. Virological studies of bird's tissues and of the tick were negative. These findings were compatible with tick paralysis or a minor equivalent of this syndrome. In addition, it was the first time that a collared dove is found as host for I. pari.

Sweating sickness in adult cattle

A Kenyan strain of Hyalomma truncatum was shown to cause sweating sickness in adult cattle in the laboratory. The typical lesions of moist eczema and mucous membrane changes were accompanied by a marked fall in circulating leucocytes with a severe neutropenia. Although all cattle recovered, some suffered a severe clinical disease and recovery was slow. Recovered cattle were immune to toxicosis 1 year later.

Tick paralysis in a western harvest mouse

An engorging female Ixodes pacificus was observed on a western harvest mouse (Reithrodontomys megalotis) in Humboldt County, California. The mouse demonstrated a flaccid paraplegia, but it appeared to recover fully after the tick was removed.

Tick paralysis in a grey fox

One hundred seventeen Dermacentor variabilis were removed from the head and back of a grey fox (Urocyon cinereoargenteus) showing paresis and diminished motor reflexes of the hind limbs. Rapid and total recovery led to a diagnosis of tick paralysis.

[The vulnerability of peripheral nerves and the somatic toxin linkage in tick paralysis of chickens, caused by Argas (Persicargas) walkerae (author's transl)]

Investigations on the impulse propagation and the pattern of amplitudes of toxically by Argas (Persicargas) walkerae larvae impaired peripheral nerves were carried out under oxygen saturated and anoxic conditions. It was demonstrated, that the maximum nerve conduction velocities of the isolated N. ischiadicus were slightly lowered in the first carbogenic and anoxic phase, in comparison with normal nerves. After the second incubation the conduction velocities were, however, almost the same or even higher. The survival times of the nerves after anoxic exposure, which were determined by the temporal persistence of the potentials, revealed that this neurophysiological parameter always resulted in a higher value for the damaged nerves after every two anoxic phases. The diseased nerves therefore tolerate anoxia longer and better than do healthy nerves in respect to their excitability and in their function of impulse propagation. From these in vitro investigations it is concluded that the noxious substance responsible for the paralysis is not cell-bound, but circulates humorally. The toxin possesses membranophilic properties, but its somatic linkage is very labile.

Paralysis of calves by the tick, Ixodes Holocyclus

Adult female Ixodes holocyclus were collected from the field at Fig Tree Pocket, a Brisbane suburb, at Tamborine Mountain, Queensland and at Lismore, New South Wales, in November 1974. Females were also reared from engorged nymphs collected off bandicoots from Tamborine Mountain July 1974 and 1975. In November 1974 unexposed 2-3 week old British breed calves, weighing between 26 and 46 kg were infested with 2,4,8 or 10 ticks. Neither 2 nor 4 females per calf caused paralysis. A challenge of 8 to 10 females induced paralysis 6 to 9 days after infestation by which time most ticks had engorged. There was little difference between ticks from different geographic localities. The site of attachment had no influence on tick toxicity. In September 1975, 2-3 week old British breed and Sahiwal x Jersey calves were infested with female ticks which had moulted 2-4 weeks prior to infestation. All but one calf with 10 ticks and all calves with 4 ticks became paralysed 8 to 13 days after infestation. At the time of paralysis only 1 of the 86 ticks had engorged and the remainder were small (30 to 50 mg). The greater toxicity of the latter ticks may have been due to the different treatment of ticks prior to infestation or to variations in the production of toxin associated with slow feeding. Four of 7 paralysed calves were saved using canine antitick serum.

Paralysis in chickens caused by larvae of the poultry tick, Argas persicus

White Leghorn pullets 20 weeks old submitted to the diagnostic laboratory were found heavily infested with the larval stage of the poultry tick, Argas persicus. The birds were severely depressed and recumbent. The signs were quickly reversed when the tick larvae were removed. The rapid rate of recovery and negative results in detailed diagnostic procedures suggested that the tick larvae caused the paralysis.

Cattle and the paralysis tick Ixodes holocyclus

Paralysis of domestic stock by the paralysis tick Ixodes holocyclus is chiefly a disease of young animals (especially calves) and of non-habituated stock introduced into tick-infested country in spring. The tick has a wide host range, but its principal hosts are bandicoots. The tick has one generation per year and the adult female, which causes almost all paralysis, is abundant in spring and early summer and occurs most commonly in overgrown or regrowth country where bandicoots are abundant. The distribution and behavior of the long and the short-nosed bandicoots are reviewed. The number of ticks required to induce paralysis in cattle and the protection from paralysis afforded by prior experience of the tick are discussed.