VN May 2017

Dermatology Quiz I Answers A DISCUSSION

ANSWERS 1. Crust can be carefully removed and crushed between microscope slides after emersion oil has been added. Search for small mites with ‘stubby’ legs. 2. Knemidokoptes pilae mite (Figure 3). 3. Separation of those birds infested with this mite since the mite is transmitted from bird to bird through direct contact. 4. Treatment of choice for birds with scaly leg mite lesions, and all birds that have had contact with them, is ivermectin. It may require 2-6 treatments at 10 day intervals to completely eliminate the mites. Ivermectin may be applied to the skin behind the neck, given orally, or injected. Moxidectin has also been used topically.

eight-legged nymphal stages from the second of which the adults emerge. In

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The mites, commonly known as ‘scaly leg mites’ and ‘face mites’, are parasites of the skin and beaks of birds. The scaly leg is also referred to as 'tassel foot'. Budgerigars and many other bird species can be parasitised by Knemidokoptes mites that feed on dead skin cells. K. pilae dissolves this dead material by means of a keratinase. K. pilae are roundish-oval mites (Figure 3). The males are up to 220 µm long and about 150 µm wide, females up to 356 µm long and about 300 µm wide. The four pairs of legs are short and stubby in shape and have five segments. At the ends of the extremities, males have unjointed grippers and suckers, while females have claws. They inhabit a single host throughout their life cycle whilst infection of a new host occurs by contact. The viviparous females burrow tunnels in the epidermis where they give birth to six-legged larvae, which mutate through two

budgerigars the eyelids, beak, cere, as well as the legs and feet can be affected and in severe cases the area around the bird's vent is affected. Interestingly, white budgies are albinos. The Ino gene is responsible for the absence of melanin, so white budgies are sometimes labelled ‘Inos’. v

Spread of diseases in farmed animals shown using social network analysis Researchers have shown that looking at movements of operators and vehicles between farms in the same way we look at contacts in social networks can help explain the spread of dangerous infectious diseases of livestock, such as foot-and-mouth disease and avian influenza. This research, published in PLOS Computational Biology , can contribute to the development of more accurate tools for predicting the spread of livestock diseases and may help implement more effective biosecurity measures in farms. The study, by researchers from the Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna, has shown that the network of contacts originated from on-farm visits by veterinarians in dairy farms of Northern Italy displays hidden features that cannot be detected by simply looking at the frequency of visits and unveils patterns of infection otherwise unexplained. The authors discovered that veterinarians' movements produce an unexpectedly large number of potentially infectious contacts between farms that can quickly spread dangerous livestock diseases. The research, made possible by the availability of high-resolution data in space and time on veterinarian movements in the study area, shed light on the actual significance of operator movements in disease spread, a still poorly understood topic due to the highly diverse and complex nature of such movements and to privacy issues in data collection. The researchers compared the role of veterinarian movements on diseases spread with those of animal exchange between farms, which is recognised as the most effective transmission route for livestock infectious diseases. They found that co-occurrence of operator movements and animal exchanges is synergistic, largely amplifying the potential for disease propagation. The study shows how multilayer network analysis substantially improves the way diseases spread can be described, thus contributing to their control. (Source: www.sciencedaily.com/releases/2017/01/170126142828.htm ) v V e t n u u s V e t n e w s V e t n u u s V e t n e w s V e t n u u s V e t n e w s FAST MAIL • BLITSPOS

28 Mei/May 2017