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Outbreaks of Cattle Disease.
During the latter part of the year, outbreaks of cattle disease occurred at Pokfulam. Acting on the instructions of the Honourable the Principal Civil Medical Officer, the Bacteriologist associated himself with the Colonial Veterinary Surgeon in order to investigate the exact nature of the outbreaks, and their mode of propagation.
The disease proved to be the same as that described in our joint report on Disease", in 1903.
"Cattle
It has been suggested that "biting flies" convey the diseases from one animal to another. These flies appear to belong to the genus Stomoxys, the commonest variety of which is the Stomoxys calcitrans. Experiments, in fly-proof sheds, are to be made to test this theory.
Observations on Hæmatozoa in Hongkong.
In Man.
Apart from Malaria, blood parasites have not been found. The Leishman-Donovan body is not present in the spleeu of Chinese in Hongkong. Cases of Spirillar Fever are met with but are always imported.
In Animals.
Frogs. Three varieties of parasites are common in frogs in Hongkong, namely
:-
1. Drepanidium.
2. Dactylosoma.
3. Trypanosoma.
These three parasites may be present together, as in Rana esculenta. A fourth doubt- ful parasite is the Entamoeba. This would appear to be simply a vacuole in the red blood corpuscle in which are found a varying number of rod-shaped bacteria. Stained preparations of these bodies, never show any definite protoplasınic structure containing chromatin. Drepanidium is most frequently found in the black spotted toad or rock frog (? Bufo melanostiches). Dactylosoma is commonest in the edible frog (Rana esculenta).
The two parasites would appear to be distinct. Trypanosoma rotatorium has been found in Rana esculenta only. It is 40-50 w. long, by 20-30 w, broad, excluding the flagellum. The latter is short and frequently contracted The body is irregular in outline, and usually has a striped appearance throughout. It shows no pointing towards either end. The nucleus and centrosoma are usually found lying close together.
Fish-Trypanosomata are the only parasites found in the blood of fish caught in the neighbourhood of the Colony. They are large in size, very an aile, and granuar. granulosum.) They are found in eels, carp, tench, salmon, bream, and barbel.
(T.
Birds.-Proteosoma is met with in sparrows and canaries. Halteridium is, however, the commonest avian hæmatozoon in Hongkong. It is found in pigeons, doves, sparrows, parrots, paddy birds, etc. Spirillosis or Trypanosomiasis has never been found.
Cattle.-Trypanosoma and Piroplasma are found. A spirochete was recently found in the blood of a buffalo calf by the Assistant Bacteriologist.
Dogs.-Pryplasmosis is found.
Horses. Trypanosomata are found.
The incidence of Filariasis is noted under the bending of Intestinal Worms.
A number
of other animals, e.g., monkeys, bats, lizards, rabbits, guinea pigs, etc., bas also been examined, but with negative results.
The Mus rattus and Mus decumanus both show the presence of Trypanosoma lewisi.