The effect of temperature and fasting period on the viability of free-living females of Rhipicephalus sanguineus (Acari: Ixodidae) under laboratory conditions

Strongyloides papillosus is found to be very common in the Lucknow area where 90% of the sheep are infected. The life-cycle is predominantly indirect, or heterogonic. The development of mature free-living adults takes place between 20° and 37° C., and 34° C. is the optimum temperature. At a temperature of 25° C., the percentage of free-living adults is 60–65 in summer (March to November) and practically 100 in winter (December to February). Immature females can develop at 40° C. in summer, but not in winter, under laboratory conditions.Inhibition experiments in a hot oven incubator with varying percentages of humidity, and in a humidity chamber incubator with constant 100% humidity, maintained at temperatures varying from 40° to 50° C., show that in the humidity chamber incubator mature free-living adults develop at 34° C. after incubation for 12 hr. at 40° C., after 4 hr. at 42° C., after 2 hr. at 45° C. and after 15 min. at 50° C. The hot oven incubator allows mature free-living adults to develop at 34° C. after 8 hr. at 40° C., after 2 hr. at 42° C., after 1 hr. at 45° C. and after 15 min. at 50° C.

Download Full-text

STUDIES ON STRONGYLOIDES OF PRIMATES: IV. EFFECT OF TEMPERATURE ON THE MORPHOLOGY OF THE FREE-LIVING STAGES OF STRONGYLOIDES FULLEBORNI

Canadian Journal of Zoology ◽

10.1139/z58-056 ◽

1958 ◽

Vol 36 (4) ◽

pp. 623-628 ◽

Cited By ~ 7

Author(s):

Premvati

Keyword(s):

Morphological Changes ◽

Effect Of Temperature ◽

Optimum Temperature ◽

Free Living ◽

Infective Larvae ◽

Complete Development

The optimum temperature for the complete development of the free-living and the infective larvae of Strongyloides fülleborni is 25 °C. Morphological changes are seen at higher or lower temperatures.

Download Full-text

Spatial epidemiological modelling of infection by Vibrio aestuarianus shows that connectivity and temperature control oyster mortality

Aquaculture Environment Interactions ◽

10.3354/aei00379 ◽

2020 ◽

Vol 12 ◽

pp. 511-527

Author(s):

C Lupo ◽

BL Dutta ◽

S Petton ◽

P Ezanno ◽

D Tourbiez ◽

...

Keyword(s):

Reproduction Number ◽

Effect Of Temperature ◽

Long Distance Dispersal ◽

Long Distance ◽

Free Living ◽

Oyster Population ◽

Marine Connectivity ◽

Oyster Mortality ◽

Adult Oyster ◽

Oyster Farms

Vibrio aestuarianus infection in oyster populations causes massive mortality, resulting in losses for oyster farmers. Such dynamics result from host-pathogen interactions and contagion through water-borne transmission. To assess the spatiotemporal spread of V. aestuarianus infection and associated oyster mortality at a bay scale, we built a mathematical model informed by experimental infection data at 2 temperatures and spatially dependent marine connectivity of oyster farms. We applied the model to a real system and tested the importance of each factor using a number of modelling scenarios. Results suggest that introducing V. aestuarianus in a fully susceptible adult oyster population in the bay would lead to the mortality of all farmed oysters over 6 to 12 mo, depending on the location in which infection was initiated. The effect of temperature was captured by the basic reproduction number (R0), which was >1 at high seawater temperatures, as opposed to values <1 at low temperatures. At the ecosystem scale, simulations showed the existence of long-distance dispersal of free-living bacteria. The western part of the bay could be reached by bacteria originating from the eastern side, though the spread time was greatly increased. Further developments of the model, including the consideration of the anthropogenic movements of oysters and oyster-specific sensitivity factors, would allow the development of accurate maps of epidemiological risks and help define aquaculture zoning.

Download Full-text