Novel Identification of Dermacentor variabilis Arp2/3 Complex and Its Role in Rickettsial Infection of the Arthropod Vector

Ticks transmit a greater variety of pathogenic micro-organisms than any other arthropod vector group, and are among the most important vectors of diseases affecting animals. A survey on the prevalence of tick species infesting domestic birds sold in Gwagwalada main market, Abuja between April and July, 2015. A total of 450 birds were examined by feather separation with fingers and a pair of forceps to expose the skin of the birds for presence of the ticks. An overall prevalence of 25.6% was observed. Out of the 150 domestic fowls examined 62(53.9%) were infested, 44(29.3%) of the 150 Guinea fowl and 9(6.0%) of the 150 Pigeons were infested. Of all the ticks identified, 93(51.4%) were from the Domestic Fowls and 77(42.5%) from the Guinea fowl and 11(6.0%) from Pigeon. Thirty (32.3%) of the ticks from the Domestic fowls were Argas persicus, 25(26.9%) Argas walkerae, 20 (21.5%) Ornithodorus moubata and 18(19.4%) Ornithodorus savignyi. Similarly, 34(44.2%) of the ticks from Guinea fowl were A. walkerae, 20(28.2%) O. moubataand 23(32.4%) O. savignyi. Five (45.5%) of the ticks from Pigeon were A. persicus, 4 (36.4%) were A. walkerae, 2 (18.2%) were O. moubata and no O. savignyi. Observation on the location of tick from the hosts body showed highest prevalence was found under the wings (55.2%) and lowest on the head & neck (5.00%). The result of this research revealed that Gwagwalada market poultry section is endemic of tick infestation. Chemical control with acaricides and improved management and sanitation of the poultry cages in the market should be enforced.

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Supercooling Points of Adult Dermacentor variabilis (Acari: Ixodidae) From a Population Near the Northern Distribution Limit

Journal of Medical Entomology ◽

10.1093/jme/tjaa223 ◽

2020 ◽

Author(s):

Matthew E M Yunik ◽

Neil B Chilton

Keyword(s):

Cold Hardiness ◽

Dermacentor Variabilis ◽

Subzero Temperatures ◽

Host Seeking ◽

Short Period ◽

Significant Difference ◽

Northern Distribution ◽

Dog Tick ◽

Provincial Park ◽

Established Population

Abstract The northern distributional limit of Dermacentor variabilis Say, the American dog tick, is expanding in Saskatchewan and Manitoba (western Canada). The ability of D. variabilis to continue to expand its range northwards will depend upon the ability of individuals within populations at the species distributional edge to withstand very low temperatures during winter. One component of cold hardiness is the supercooling point (SCP), the temperature below 0°C at which an individual freezes. In this study, the SCP was determined for 94 questing D. variabilis adults (44 females and 50 males) from an established population near Blackstrap Provincial Park in Saskatchewan. SCP values ranged from −18.2 to −6.7°C, with a median of −13.3°C. This suggests that host-seeking D. variabilis adults differ in their ability to survive exposure to subzero temperatures, for at least a short period of time, without freezing. The distribution of SCPs was bimodal, but there was no significant difference in SCP values between female and male ticks, and no relationship between SCP and tick body weight. It remains to be determined what factors contribute to the variation in SCP values among questing D. variabilis adults.

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Experiments on Oral Secretion of the Rocky Mountain Wood Tick, Dermacentor andersoni Stiles (Acarina: Ixodidae)

The Canadian Entomologist ◽

10.4039/ent891-1 ◽

1957 ◽

Vol 89 (1) ◽

pp. 1-5 ◽

Cited By ~ 20

Author(s):

J. D. Gregson

Keyword(s):

British Columbia ◽

Pacific Northwest ◽

Rocky Mountain ◽

Dermacentor Variabilis ◽

Oral Secretion ◽

Amblyomma Maculatum ◽

Dermacentor Andersoni ◽

The Pacific ◽

Tick Paralysis ◽

Rocky Mountain Wood Tick

Tick paralysis continues to be one of the most baffling and fascinating tickborne diseases in Canada. It was first reported in this country by Todd in 1912. Since then about 250 human cases, including 28 deaths, have been recorded from British Columbia. Outbreaks in cattle have affected up to 400 animals at a time, with losses in a herd as high as 65 head. Although the disease is most common in the Pacific northwest, where it is caused by the Rocky Mountain wood tick, Dermacentor andersoni Stiles, it has lately been reported as far south as Florida and has been produced by Dermacentor variabilis Say, Amblyomma maculatum Koch, and A. americanum (L.) (Gregson, 1953). The symptoms include a gradual ascending symmetrical flaccid paralysis. Apparently only man, sheep, cattle, dogs, and buffalo (one known instance) are susceptible, but even these may not necessarily be paralysed.

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Rickettsial Infection (Heartwater) in Sheep and Goats in the Sudan

British Veterinary Journal ◽

10.1016/s0007-1935(17)44354-5 ◽

1960 ◽

Vol 116 (3) ◽

pp. 105-114 ◽

Cited By ~ 12

Author(s):

Gaafar Karrar

Keyword(s):

Rickettsial Infection ◽

Sheep And Goats

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Tick Ecdysteroid Hormone, Global Microbiota/Rickettsia Signaling in the Ovary versus Carcass during Vitellogenesis in Part-Fed (Virgin) American Dog Ticks, Dermacentor variabilis

Microorganisms ◽

10.3390/microorganisms9061242 ◽

2021 ◽

Vol 9 (6) ◽

pp. 1242

Author(s):

Loganathan Ponnusamy ◽

Haley Sutton ◽

Robert D. Mitchell ◽

Daniel E. Sonenshine ◽

Charles S. Apperson ◽

...

Keyword(s):

Hormonal Regulation ◽

Natural Populations ◽

Blood Feeding ◽

Dermacentor Variabilis ◽

Transovarial Transmission ◽

Rickettsia Species ◽

Adult Females ◽

Dog Tick ◽

Total Bacteria

The transovarial transmission of tick-borne bacterial pathogens is an important mechanism for their maintenance in natural populations and transmission, causing disease in humans and animals. The mechanism for this transmission and the possible role of tick hormones facilitating this process have never been studied. Injections of physiological levels of the tick hormone, 20-hydroxyecdysone (20E), into part-fed (virgin) adult females of the American dog tick, Dermacentor variabilis, attached to the host caused a reduction in density of Rickettsia montanensis in the carcass and an increase in the ovaries compared to buffer-injected controls. This injection initiates yolk protein synthesis and uptake by the eggs but has no effect on blood feeding. Francisella sp. and R. montanensis were the predominant bacteria based on the proportionality in the carcass and ovary. The total bacteria load increased in the carcass and ovaries, and bacteria in the genus Pseudomonas increased in the carcass after the 20E injection. The mechanism of how the Rickettsia species respond to changes in tick hormonal regulation needs further investigation. Multiple possible mechanisms for the proliferation of R. montanensis in the ovaries are proposed.

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