South African Pathogenic Ticks.*

The Vetermary '7ournal. dual or multiple character was assigned, some distinguished between avian and all others, some separated the bovine type. But it is seen that nearly all bacteria vary in some or all of these characters under different environments, in artificial media especially, then why not in a living nost, and it was found in the case of the tubercle bacillus that after a time it would adapt itself to growth in media living and artificial which were considered before as incapable of nouri shing it. And the tendency to consider the different varieties as si milar or very close relations grew. vVe read some years ago the idea expressed by Straus that "the differences between the two bacilli are certainly very strikin g, but is it not possible that there may be transition forms between the two bacillary varieties? In other words, are not the two bacilli merel y races of the same organism and not actually distinct species?" This view, of course, is now widely held. Again the bovine race was formerly considered to be immune to the glanders bacillus, but experiment has shown that after some trials this organism may adapt itself to life in a bovine medium. The inference is that we may find a closer relation ship between hitherto dist inct di seases of men and animals which may aid us in the consideration of the production of immunity in each case. REFE RENCE TO Al'D QUOTATIONS FROM T H E FOLLOWING W ORKS .

"Immunity in Infectious Diseases." "Principles of H ered ity."

METCHNIKOFF. REID .

SOUTH AFRI CAN PATHOGEN IC TICKS.* By H. E. LAWS, B.Sc., F.I.C . Th e Cooper Laboratory f or Economic Research, Watford.

workin g on the subject of ticks and their eradication In South Africa the writer has often had occasion to refer to publication s and general literat ure in connectio n with thi s work in orde r to refre sh his memory on different points re garding the life-history of the variou s species of ticks , and the period s of incubation of the di sease which they transmit. Before obtaining the information desired it has often been WHILST

*

From the Agric. lourn. of th e Union of South Africa.

TABLE I. - RE LAT IO NSHIP BETWEEN DI SEASES AND THE SOUTH AFRICAN PATHOGENIC TICK S WHICH TRANSMIT THEM .

Causative organism

Disease

Incubation period

Susceptible

An imals

I

Duration of infectivity in recovered

Spec ies of ticke;. tran smitting infection

Geographical distri bution

B oophilus decolora/us (the blue tick)

South Africa to Cen tral Africa

H osts

Moults

animals

bigetlli11U,IIl

17- 18 Cattle 12 years and days more

at whi ch disease is transmitted

- - - - --

---

Pi1'oplasma

Redwater

I history Phase of lif. of tick

Cattle; other ' 1st, on } host domestic 2nd, on

Larva

animals

occasionally Rhip icephalus appe1tdiCltla/us (the brown tick)

Ditto

r

Cattle ; horses; 1St, off h t other domestic 2nd, off os

Ditto

animals ;

antelope; hare; &c. Pi roplasma ( Theileria) parvum

East Coast Fever

--

10-20 days

Ditto Non-infective Rhipicephalus appendiCltlatlis after recovery

Ditto

Ditto

Ditto

Nymph and ad ul t

Rhipicep halus capensis (the Cape brown tick)

South Africa

Cattle and other domestic animals

Ditto

Ditto

Rhipicephalus simus (the black -pitted tick )

Africa

Cattle and other rlomestic animals ; wild animal s

D itto

Ditto

TARLE

Causative organi sm

Di :-.ea se

------

In c u hation pe riod

s uscep-\ tihl. Animal '

Dura ti on o f infectivity in recovered a nim als

I. - (COll t/1tUed. )

S pecies of ti cks tran smilti ng infecti on

Geographical

Nhlji(e/,hal lts evertsi (th e red ti ck)

Africa

Phase of life -

d is tr ibut io n

I P;"oplasma lIIula lls

3- 4 week s

Nhipicephallts appmdiClilatus Cattle I I nfect ivity ; retained aft er Rhipicephalus sililus 1 r!covery

I Spirochcetos;s . Spirochtl'ta theilen'

Bil iary fever of horse

PiI'oplaslila

Moults

All domesti c animals, excepting pig; many wild animals

1s t , on } host 2nd, o ft

Adu lt

See abovt.

' at which diseas is tran smitt ed

--.-- - - - - I

East Coast Fever (continJled) .

Gall -sickness

history of lick

H os l:-o

-

See

See above Ditto I

ab~ve

Ditto

Ditto

Nymph and ad ult Ditto

Ditto

Ditto

Adu lt

See above

See above

R h;picephalus everts;

Ditto

Boophilus decoloratllS

See above

Rhipicephalus sim lls

Ditto

Ditto

Ditto

Nymph and adult

I

I

Cattle, 1 Horse' l Sheep

D itto

-

Horse

Ditto

Rhipicephal us evertsi

Di tto

Ditto

Ditto

Adu lt

-

Dog

Ditto

./J(, maphysalis leach; (the Cape-dog tick)

Africa, Southern Asia, Australia

Dog

1 st, off } host 2nd, off

Di tto

All domest ic and many wild animals

Ditto

Nym ph and adult

I

La rva

equi

Maligna nt Piroplasma jaundice of dog canis Unknown

Heartwater

I

About Sheep, Non-infective IS days Goats, after recovery Cattle

A mblyolllma hebrtl'u1/I (the bon t tick)

I Sout~:fri ca Central Africa --

* Donitz, \ V_ (1910), "Die Zecken Siidafrikas ," p_ 430.

,. -

P E RIO QS O CC U PIIW BY THE VARIOU S P HASES OF THE LIFE-IllSTORY O~' SOME SOUTH AFRI CAN PATHOG(;N IC TI C KS_

TA BLE II. -

...

"'-I

Dropping off S pec ies

la~va::

Time I droppin/: off

of rep lete

Time from egg-laying to

fe ma le

ha tchi ng out

with o ut

o f br viJ·

for

of Ian ££!

fceding

on repletion

firs t mo ult.

10

eg g-la yin g

Time

can eXI st

10

Time on grollno

Tim e to

drop pirg of nym ph

on reple tion

- - - - - - - - -- - - - - - - -- - -- - - - - - - 1---B oopMlus decolo- 5 days o r 3- 6 weeks I 6 month s mtus (the B lue

mo re ac cordi ng to season

Tick)

R hipicep l,allls ap pcltd i c ll la tll s

6 d ays

mo re w in ter

-

In

Tim e

nymp h can ex ist with o ut

feeding

I

I I

Tim e on g ro un

tor second mou l L

--I --

I I

I

.

I

28 d ays to

i 7 mo nths

3- 8 days

s e v e r al mo nths

(the Brown Tick)

I

Abo nt days

21

A hont days

20

3--7 day s

6A- mon ths 1\ 1> 0 u t •

d ays

Time Lo

Ti me ad ult ca n exi s t with o ut fcedi ng

dropping of ad ult fe males on rep le ti on .

3 - 4 weel

l

R hiticephal{(s Il itens (th e S hiny ,Brown Ti c k) •

R hipicepltallfs capmsis (th e Cape Bro wn Ti ck ) •

R hipicepltaills si mlfs (th e Bl ac k pitted Ti ck )

R llipiceph aills

t

tV-

,,-l si (th e R ed Ti ck )

A mbl)'o11l l/la

Ile-

b,.,FIIIIl (the Bon t Ti ck)

w eeks to

2

mll re t ha n

3

1l 10 1lll ,S

Abou t d a ys

30

A I,out days

30

10

,,-eeks to mon ths

JO

7 mo nt hs

I

mon ths

4 -

20

da ys

m os tly f rom

5 - 7 days

2;

Abon t d~ y s

to

4

4-

20

daIs

Ab out d ays

25

A bout day;,

24

6 months I 25-- [ 60 days

'l' on th s

• Li fe cy cle rese mhles tha t of R ilipiceplw / us appelldiotlalllS , accord ing to Th eiler.

t R hipicephalus Jimus nsna ll y feed s on sm a ll wild anim als d llr ing it; la r val a nd nymphal stages.

[ yea r

7 mon ths

t o -- 20

day,

The Veterinary Journal. found nece ssa ry to read through an enormous number of papers, which obviously involves a g reat waste of time, beside being extremely laborio us . In order to avoid as far a s po ss ible this unnece ssary labour it has occurred to the writer-and no d0ubt other workers have found th e need for it too- that it would be a tremendous as sistance to tho se interested in the subject of ticks, both professionally and as practical farmer s, if tables were compiled giving the more ess ential points in connection with the habits and life-hi storie s of tick s and the di sea ses which they tran smit , so that one can refer to them without finding it nece ssary to read throu g h an enormous amount of detail before arriving at the actual information required. The writer has discussed this with Mr. Robinson of thi s Laboratory, and the latter has been goo d enough to draft two tables, No. I showing the relation between South A frican Pathog enic Ticks and the di seases which they tran smit, No.2 showing the periods occupied by the various phases of the life-history of some South African Pathogenic Ticks. In order that the tables may be of service to the practical man, as well as others, Mr. Robinson has in serted the popular names of the diseases as well as those of the ticks which transmit them. ROYAL (DICK) VETERINARY COLLEGE, EDINBURGH . Al' a recent me etin g of the Board of Management of the Royal (Dick) Veterinary Co ll ege, Edinburg h, it wa s intimated that the purchase of a site for new co lle ge buildings had been concluded. The site, extending to about one and a half acree:;, is on the east side of the Meadows, and within easy reach of th e University. The co st of the new buildings , which will be CO!;) · menced without undue delay, is estimated at £50,000.

DEATH OF SIR RUBERT BOYCE, F.R.S .

.

WE regret to announce the death of Professor Sir Rubert

Boyce, which occurred suddenly at Liverpool , as the result of an apoplectic seizure. Sir Rubert was an excellent friend to the veterinary profession and it was mainly through his instrumentality that the Veterinary School of the Liverpool University was established.