Streptothricosis in the Domestic Donkey (Equus Asinus Asinus). I. Clinical observations and Clinical Pathology

Br. vet.

J.

(1971), 127, 572

STREPTOTHRICOSIS IN THE DOMESTIC DONKEY (EQUUS AS/NUS AS/NUS). I. CLINICAL OBSERVATIONS AND CLINICAL PATHOLOGY BY D. H. LLOYD Department of Veterinary Pathology, University of Ibadan, Nigeria

SUMMARY The clinical aspects are described of an outbreak of streptothricosis in a group of donkeys which were observed over a period of five and a half months. The progress of the disease appeared to be related to the humidity and rainfall. Stress factors had no significant effect on recovery from the disease. INTRODUCTION Streptothricosis in its widest sense may be taken to mean skin disease caused by the aerobic actinomycete, Dermatophilus congolensis. Its various manifestations in different species of animals and in different parts of the world have been given a variety of names (Memery & Thiery, I 960) but all are characterized by the development of a proliferative, exudative dermatitis with scab formation, in smears of which the characteristic branching mycelium of Dermatophilus congolensis, dividing into transverse rows of cocci, may be demonstrated. This organism has a wide host range and apart from the commonly affected domestic animals such as cattle, sheep, goats, and horses, the natural disease has also been reported in the pig (Vandemaele, I96I; Stankushev, Simov, Denev, Kyurtov & Aleksandrov, I968), chamois (Nicolet, Klinger & Fey, I967) deer (Dean, Gordon, Severinghaus, Kroll & Reilly, I 960; Nicolet, I 970 personal communication; Kistner, Shotts & Greene, I97o), eland (Hornby, I92o), kudu and cephalophe antelope (Vandemaele, I 96 r), giraffe (Austwick & Davies, I958), various gazelle (Anon, I954; Austwick & Davies, I958), zebra (Green, I96o; Vandemaele, I96I ), Columbian ground-squirrel (Wobeser & Gordon, I 969), cottontail rabbit (Shotts & Kistner, I 970), and in man (Harriss, I 948; Dean et al., I 960; Kaplan, I 966). Streptothricosis in the donkey was diagnosed by Green (I 960) in Kenya during the examination of dried skins. Gramstained smears of small scabs from mild lesions along the dorsal midlines revealed the typical segmented filaments of the causative organism. The present report describes the clinical aspects of an outbreak of streptothricosis in a group of nine donkeys which were observed over a period of five and a half months in Ibadan, Nigeria. The bacteriological and immunological aspects of this outbreak will form the subject of a separate report. CLINICAL OBSERVATIONS Nine donkeys were obtained in Zaria, in the North-Central State of Nigeria,

STREPTOTHRICOSIS IN THE DONKEY

573

in June I970 and brought to Moor Plantation, Ibadan. They were housed in fly-proof pens and fed on guinea corn and grass which was gathered from nearby fields; they were allowed out to graze for approximately two hours daily whilst their pens were cleaned. According to the animal attendants all were in good condition on arrival and had smooth healthy coats; however, their condition deteriorated steadily and on 17th September I970, when they were first seen by the author, all were thin, their coats were rough and scabs could be observed or palpated in areas of raised hair and in the mane and tail (Fig. I, 2). Each donkey was examined on four separate occasions, the coat being palpated and the mane and tail parted to reveal the presence of scabs and ectoparasites. On the first examination samples were taken wherever scabs were found but on subsequent occasions scabs similar in location and appearance to those seen previously were not sampled . Table I lists the sites in which streptothricosis lesions were found on each visit. Three types of streptothricosis scab could be differentiated. On the trunks of the donkeys scabs were relatively thin and loosely knit with a flakey appearance (Fig. I), whilst scabs found in the mane and tail were much thicker, harder and remained firmly attached to the hair as it grew out (Fig. 2). Scabs on the limbs were on the whole small and discrete, having a typical "paintbrush" appearance. vVell formed scabs had a concave undersurface, and when active lesions were detached from the skin they revealed a red, moist and sometimes haemorrhagic skin surface. In general the scabs were small, varying in diameter from about 3 mm to I em and in thickness from about 2 mm to I ·5 em; the biggest scabs were found in the tail, the smallest in the ears and on the limbs. The locations of the lesions were as follows. On the muzzle they were situated antero-dorsally, proximal to the nostrils; on the ears they were found on the hairs arising from the base of the margins of the pinna; in the mane they were found principally in the hair over the nuchal crest; on the back lesions were concentrated along the midline particularly over the withers, at the middle of the back and over the sacrum; other lesions on the trunk were found chiefly over the dorsal half of the thorax. On the tail the largest scabs developed at the extreme end with smaller scabs arising from the area around it; more proximal areas were not affected. One donkey (number 7) developed a lesion approximately I em in diameter, on the left ventro-lateral margin of the anal orifice. Lesions on the limbs were found postero-laterally particularly at the knee, hock and fetlocks. Many scabs were examined in which D. congolensis could not be demonstrated; however, these generally had a flat, thin, appearance unlike that of positive scabs. The bodily condition of the donkeys and their management varied during the period of observation (Table II). When first seen the donkeys were in poor condition and two of them (numbers 2 and 6) were emaciated; a few ticks of the species Boophilus decoloratus could be found on all of them and a single Amblyomma variegatum was found on number I. Investigation of the feeding arrangements revealed that the amount of grass given to the donkeys

(JI

II ~

TABLE I SITE

DISTRIB UT I ON OF STR EP T O THRI COS IS LESIONS ON EAC H

DONKEY

AT EAC H

VISIT

Identification of donkeys affected Site Visit I

Visit II

Visit III

I 7 / 9 /70

13/ 10/ 7 0

26/I0/70

Muzzle Ears

5o

II

III

IV

I

-

-

-

I

5

I

-

-

5

2

I

I

-

2

2

I

-

-

2

I

-

-

-

I

-

I

-

2

-

-

-

2

I

I

-

-

I

5

4

4

I

5

II ~ r

7

-

I

-

-

I

:;-'

5o 7

2

3

-

-

3

5

3

3

-

-

4

I

6, 9

I,

5

I

M a ne

2,

6

2

Withers

7 I,

Tuber coxae Tail

6

I

I , 3>

I

5o 8,

9

I , 3,

Perinaeu1n

Trunk

I

I

Mid-back

I ,

5

I>

Site frequency*

I

Nuchal crest

Sacrum

I 0 / 2 / 7I (g) 3/3/71 (rest )

I I , 2,

Number of donkeys with lesions per visit

Visit IV

5o

9

1, 3,

5o

9

9

......

Number of donkeys examined per visit

I,

4, 5

9

1 0 2,

8

8

6

en

::r:

<: trl

>-3

I

Limbs above knee/hock Limbs below kneefhock

I I >-3~

*Number of times each site was affected during the period of observation.

trl

::0 ......

z

I~ c

~ ~

STREPTOTHRICOSIS IN THE DONKEY

575

was grossly inadequate and arrangements were then made to allow them to graze for most of the day. This regime led to some improvement in the condition of all except number 1 which showed no improvement and number 6 which died on 29th September, 1970. No autopsy was carried out and the cause of death was not determined. However, the donkeys were now subjected to intense fly attack (Stomoxys calcitrans and Musca domestica) concentrated on the lower parts of the limbs causing bleeding points and granular encrustation of dried blood particularly around the knees, hocks, and fetlocks. In spite of the fly attack the number of areas affected by streptothricosis decreased as detailed in Table I, and the extent of the lesions was also reduced. Faecal samples taken at this time showed that all the donkeys except number 8 were heavily infested with strongyle nematodes, and they were accordingly treated with pyrantel tartrate * at the recommended dose rate. A further improvement in condition was apparent on the third visit on 26th October, 1970 in all except number 1, which was as before, and numbers 7 and 8 whose condition had deteriorated. Number 7 was dull and recumbent most of the time, and was suffering from decubitus. The cause of this loss of condition was not diagnosed. However, the donkeys were now more heavily infested with Boophilus decoloratus, particularly numbers 1 and 7 on which they were thickly clustered on the head and neck and especially in the ears and the mane. The final examination was carried out in two parts as donkeys 1, 2, 3, 5 and 8 had now been moved to Agbowa-Imota in Lagos State. Only number 9 remained at Moor Plantation, 4 and 7 having been sacrificed for experimental purposes unconnected with this report. Donkey 9 was examined on loth February 1971, the others on 3rd March, 1971. The condition of all the animals had again deteriorated and donkeys 1, 3, and 9 showed clinical signs of epizootic lymphangitist on the limbs. A few Boophilus decoloratus could be found on all the donkeys and one male Rhipicephalus evertsi was found on donkey 9. All the donkeys at AgbowaImota had severe, purulent annular lesions on their fetlocks (2 limbs per animal) due to incorrectly applied hobbles. However the only streptothricosis lesion found was on the tail of donkey 9.

* Banminth

(Pfizer) .

t Subsequently confirmed by histological examination. TABLE II BODILY CONDITION OF DONKEYS

2

Date 22/9/70 17/10/70 26/10/7 0 10/3/7 1 3/3/7 1

3

4

Donkey No. 5

6

8

7

9

++ + ++ ++++ +++ +++ +++ ++++ ++ ++ ++ +++ ++ ++ ++ ++ ++ +++ +++ + + + + + ++ + + ++ ++ ++ ++ ++ K ey : Moderate

= +,

Thin

= ++, Very thin = +++, Emaciated

=

++++ .

BRITISH VETERINARY JOUR AL,

127, 12

TABLE Ill RATE

OF

GROWT H

OF DONKEY TAIL

HAIR

Period of growth (days )

Length (mm )

Rate (mm fday )

9

97

45

1)•46

2

1r g

43

0·36

7

119

47

0"39

Donkey No.

3

11 9

50

0"42

5

11 9

52

0"44

Average rate = 0·42 mmfday. TABLE IV DATE OF ORIG I N OF TAIL SCABS

Donkey no. 3

Tailfscab* distance (mm )

Age of scabs** (days )

Estimated date of onset

45"0

107

12th july, 1970

5, Scab

I

37"5

85

4th August, 1970

Scab

2

27"5

63

24th August, 1970

9, Scab 1

10"0

22

5th O ctober, 1970

Scab 2

23"0

50

7th September, 1970

* Distance from the skin surface to the distal face of the scab. **Using the individual rates from Table III.

CL I N I CO -PATHOLO G I CA L OBS E RVATION S

Af aterials and methods Scabs were ground in sterile distilled water in sterile Griffiths tubes and thick, heat-fixed, smears prep ared, stained by Grams m ethod and examined for the presence of the typical gram positive fil aments and multiple rows of cocci of D. congolensis. The emulsified scab prepara tion was allowed to stand at room temperature (about 22 °C) for at least half an hour when thin wet preparations were made and examined by phase contrast microscopy for the motile zoospores of D. congolensis. Isola tion of the organism was achieved by culture on 5 per cent horse blood agar, directly from scab suspensions or after filtration through I ·2 nm millipore filters. Blood for haematological and serological studies was collected at various times (sec T able V). The following haematological values were determined ; packed cell volume, using the microhaematocrit m ethod; h aemoglobin es timation by photoelectric colorimetry of oxyhaemoglobin after haemolysis with o·o4- per cent ammonium hydroxide; and white blood cell count by haemocytometer. Giemsa-stained blood films were used for differential white blood cell counts and examination for presence of blood pa rasites.

STREPTOTHRICOSIS IN THE DONKEY

577

TABLE V HAEMATOLOGY

Jlf

2 F

3 AI

26

29

'7/ 10/ 70

27

26/ 10/ 70

25

I

Packed cell volume (per cent ) Date: 22/9/70

Donkey no. and sex 4 5 F

Jlf

6 M

F

7

8 F

9 F

29

30

28

25

26

30

27

28

25

26

26

20

30

22

22

24

27

26

19

28

22

27

28

'7

29/10/70

23

24

27

10/2/71 3/3/7 1

24

22

22

Haemoglobin concentration (gj10o ml ) Date: 22/9/70

7'70

8·73

8· 58

8·88

8·44

3'

30

50

26

7'84

9'03

8·14

25

7"55

17/ 10/ 70

7' 99

8·29

7'70

7'99

7'70

6·22

8·88

6·8J

26/ 10/ 70

7'70

6·81

7'70

8· 5 8

7'99

s-63

8·88

6·96

29/ 10/70

7'1 0

7'40

8· 58

8· 5 8

8·88

5"03

9' 77

9'47

10/2/7 1

7'40

14·8o

8·29

6·s'

6·s'

7'70

3/3/71

White blood cell cowzt (103fmm 3) Date: 11 ·6o 22/9/70

15"1 5

12'05

14'45

15"45

18·90

14·6o

14'05

9'75

15·6o

14'45

I3'70

I2'70

I I'25

IS"25

2I'90

12'IO

18·15

I3'25

I2'10

13'00

10·8s

13·8o

15'15

I7·6s

12'90

9·6o

15'20

I

I'95

12'70

I 1'55

IS"85

18·6s

26'30

15 '50

17/10/ 70 26/ 10/70 29/10/70

11'55

10/2/71 3/3/71

26·so

11 ·80

24'15

An attempt was made to determine the date of origin of the outbreak by measuring the distance from the skin at the tip of the tail to the distal surface of the streptothricocis scabs attached to the tail hairs, during the third examination (26th October, 1970) on donkeys 3, 5 and g. The rate of growth of the tail hair was then determined as follows. The tail hair of a number of the donkeys was cut flush with the skin at the tip of the tail and the increase in length measured during the last visit. Meteorological data were obtained from the Moor Plantation meteorological recording station of the Federal Department of Agricultural Research.

BRITISH VETERINARY JOURNAL,

127, 12

TABLE VI NORMAL DONKEY

HAEMATOLOGY-DATA FROM THE

LITERATURE

( Cited by Schalm, 1961 )

WBC Origin

Sex

N o.

( I03jmm3)

PCV(% ))

Neser (1923)

South Africa

Both

14/32

11"5-21"9 (14"4)

3o-48 (37)

Wilding et al. (1952)

South-Western U.S.A.

Male

16

7•o-17"7 (12·6)

31-45 (36)

Female

12

9·3-28·5 (14'4)

26- 5 1 (37)

Author

"Burros"

Hb (g( 10oml )

9"3- 1 5"5 (u·61 )

RESULTS

Scab examinations. D. congolensis was identified in stained smears and motile zoospores were observed in wet preparations from every positive site (Table I) on each donkey on at least one occasion. The organism was isolated in culture from all except donkeys 3 and 4· Tables III and IV give details of the measurements made, the rates of growth of donkey tail hair and the estimated dates of origin of the tail scabs. Relative humidity • - • 0900 hr G.M.T. 9 0 o--o 1500 hr GMT.

85

80 75

13

c "'~ "'a.

70 .~

II

65

10

60

9

55 -~ 0

"0

E

"

.<:

"'

50

-8 .~

- 7

45

~

.?:-

"6

"0

0

c

0

::;: "'

:s 6

0

0:::

5

35

4

30

3

2

O L-~~~~~-~~~--~~~~~

MoyJune July Aug.Sept. Oct . Nov Dec . Jon . Feb. Mor. 19 70 1971

Fig. 3· Climatic conditions at Moor Plantation, May 1970 to March 1971.

STREPTOTHRICOSIS IN THE DONKEY

579

Haematology. The results of differential white cell counts are not given, but were generally within the range quoted by Neser (I923 ). The other haematological values obtained are given in Table V. All the donkeys were found to have low Babesia (Nuttalia) ·equi parasitaernias indicative of carrier status, throughout the period of observation, with the exception of number 8. Climatic conditions. The climatic conditions prevailing at Moor Plantation during the period of observation are illustrated in Fig. 3· DISCUSSION

This outbreak occurred in a group of animals shortly after they had been removed from their normal environment in the Northern Guinea Savanna and brought south to the relatively humid forest zone in which Ibadan is situated. Their arrival in Ibadan coincided with the short dry period in the middle ofthe rains, which is characteristic of south-western Nigeria (Buchanan & Pugh, I 955); Fig. 3 shows the climatic conditions prevailing at that time and throughout the period of observation. It can be seen that although there was decreased rainfall in the early part of this period, the relative humidity continued to rise, reaching an ogoo hours G.M.T. peak of 8g per cent for the month of August. Peak rainfall occurred in September, and then rapidly decreased to nil in December, the build-up for the following rainy season beginning in February. The course of this outbreak appears to have a close correlation with these climatic changes. The first lesion to occur on the tails, as deduced by calculations based on the rate of growth of tail hair (see Tables III and IV) arose in early July (donkey 3) shortly after the arrival of the donkeys in Ibadan, and donkeys 5 and 6 were subsequently affected in August and September. When first examined on September I 7th a total of 25 sites were involved on all the donkeys (Table I) and this number decreased progressively with each visit, until on the last occasion only one site was affected. It is considered unlikely that tail lesions which might have arisen before the earliest one reported here were missed as donkey tail hairs commonly grow to lengths of go centimetres (Lloyd, unpublished observations) which at the average rate of growth found in this study (0·42 mm per day) would take nearly two years. In addition, the scabs are tenaciously attached to the hairs and the author has observed scabs attached to donkey tail hairs at distances of up to I r '5 em in the Northern States of Nigeria. These findings agree with reports of streptothricosis in other species of animals in which the disease has commonly been related to periods of high rainfall and increased humidity (Memery & Thiery, Ig6o; Vandemaele, I96I; Roberts, 1967; Oduye & Lloyd, 1971). The role of these factors has been particularly stressed in reports of outbreaks in the horse, the only other member of the Equidae in which streptothricosis has been diagnosed (Scarnell, I961; Bentinck-Smith, Fox & Baker, 1961; Kaplan &Johnson, Ig66; Kelly & Knappenburger, 1968; DiSalvo & Kaplan, I969); indeed in Ibadan streptothricosis in the horse is seen only during the rains (Hill, 1971, personal communication). The possible role of stress factors other than change of environment must also

580

BRITISH VETERINARY JOUR AL,

127, 12

be considered. Malnutrition was evident when the donkeys were first seen and ticks were present although not in great numbers until the third visit. Intense fly attack occurr~d following the first visit, and heavy strongyle infection in all except one donkey (number 8) was diagnosed following the second visit. Again, with ,the exception of number 8 all were consistently shown to have Babesia equi parasitaemias. Finally at the last visit epizootic lymphangitis was diagnosed in.three of thedonkeys. Ticks and.particularly Amblyomma variegatum have often been incriminated in outbreaks of streptothricosis in other species (Hobday, 1953; Plowright, 1956; Mammerickx, 1961; Macadam, 1964) and Macadam (1961 ) transmitted the infection from affected to unaffected animals by means of ticks (Amblyomma variegatum) . Similarly flies have been incriminated (Calderbank, 1951; Wilson, 1958; Macadam, 1964) and Richard & Pier (1966) transmitted D. congolensis infection from experimental lesions on rabbits to the intact skin of unaffected rabbits with both Stomoxys calcitrans and Musca domestica. Intercurrent disease and factors causing d ebility have also been suggested at various times as being involved in the onset of streptothricosis (Plowright, 1955; Memery & Thiery, 1960; Braibant, 1962); intercurrent disease (strongyliasis, epizootic lymphangitis, babesiosis) and debility were certainly present at various periods during this investigation. However, if one attempts to relate the onset or intensity of the various stress factors mentioned above with the chronological development of the outbreak, it is plain that their individual effects, if any, did not exert a significant effect. In spite of the increase in tick infestation. the intense fly attack, heavy intestinal parasitism and intercurrent .infection, the number of sites affected and the severity of individual lesions decreased progressively from the first examination. Analysis of the haematological data obtained during this study shows that generally the values for packed cell volume and haemoglobin were low when compared with the findings of Neser (1923) for donkeys in South Africa and of Wilding, Kimball, Whitaker, Trum & Rust (1952) for United States burros whilst white blood cell counts were generally within the ranges given by these authors (Table VI ). Values for the differential white cell counts varied, but generally remained within the range quoted by Neser (1923) . However, no relationship could be demonstrated between the degree of affection with streptothricosis and the haematological findings . ACKNOWLEDGEMENTS

Thanks are due to Professor B. O. Amure and Dr M . O . Olowo-Okorun for permission to study these animals, to Dr L. P. Joyner for confirmation of the identity of Babesia (Nuttalia ) equi and also to Mr K. W. Head for his assistance in the prepara tion of the text. REFERENCE S ANON. (1954), E. Afr. Veld, 3, 67· AUSTWlCK, P. K. C. & DAVIES, E . T . (1958). Vet . Rec. 70, 108r. BENTINCK-SMITH, J ., Fox, F. H. & BAKER, D . W. (1961). Cornell Vet. 51,334. BRAIBANT,1. ( 1962). Bull. epizoot. Dis. Afr. 10, 517. BUCHANAN, K. M . & P UGH, C. ( 1955). Land and People in Nigeria. London:

J.

London Press.

University of

PLATE I

Fig.

1.

Loosely knit scabs on the thorax of donkey

Fig.

2.

Scabs in the tail of don key

1.

1.

Lloyd, Br. vet.

J. ( I 97 I),

127, 12

STREPTOTHRICOSIS IN THE DONKEY CALDERBANK, G. (rgsr). Proc. sth Vet. Dept. Conf (Nigeria), 25. DEAN, D. J., GoRDON, M.A., SEVERINGHAUS, C. W., KROLL, E. W. & REILLY, J. R. ( rg6o) . Ann. Rep. N.r. St. Dept. Hlth, Lab. Res. 56. Dr SALVO, A. F. & KAPLAN, W. (rg6g). Vet. Med. 64, 502. GREEN, H. F. (rg6o). Vet. Rec. 72, rog8. HARRISS, s. T. (rg48). ]. comp. Path. s8, 314. HoBDAY, J. H. N. ( 1953). Ann. Rep. Dept. Vet. Serv., Northern Rhodesia. HoRNBY, H. E. (rg2o). Vet.]. 76, 210. KAPLAN, W. (rg66). ]. Am. med. Ass. 198, 42. KAPLAN, W. & jOHNSON, W. J. ( rg66). ]. Am. vet. med. Ass., 149, r 162. KELLY, D. C. & KNAPPENBURGHER, T. E. (rg68) . Vet. Med. 63, !055· KISTNER, T. P., SHOTTs, E. B. & GREENE, E. W. ( 1970). ]. Am. vet. med. Ass., 157, 633. MACADAM, I. (rg6r). Vet. Rec. 74, 643. MACADAM, I. (1964). Vet. Rec. 76, 194· MAMMERIKX, M. (rg6r). Annis Soc. beige Med. trop. 41, 133· MEMERY, G. & THIERY, G. (r96o) . Rev. Elev. med. vet. Pays trop. 13, 123. NESER, C. P. (1923). 9th and roth Rep., Dir. Vet. Educ. and Resea~ch, p. 479· Pretoria: Union of South Africa. NrcOLET, J., KLINGER, K. & FEY, H. ( 1967). Path. Microbial. 30, 83 r. 0DUYE, 0. 0. & LLOYD, D. H. (rg7r). Br. vet. ]. 127, 505. PLOWRIGHT, W. (1955). Bull. epi;coot. Dis. Ajr., 3, 28r. PLOWRIGHT, W. (1956). Vet. Rec. 68, 350. RrcHARD, M.S. & PrER, A. C. (r966) . Am.]. vet. R es., 27, 419. ROBERTS, D. s. (r967)· Vet. Bull. 37· srs. ScARNELL,j. (r96r). Vet . Rec., 73, 795· ScHALM, 0. W. (r96r). Veterinary Hematology. Philadelphia: Lea and Febiger. SHOTTS, E. B. & KisTNER, T. P. (1970). ]. Am. vet. med. Ass. 157, 667. STANKUSHEV, KH., SrMov, I., DENEV, I., KYURTOV, N. & ALEKSANDROV, M. (1968). Vet. Sbir. Sof 6s, 3· VANDEMAELE, F. P. (r96r). Bull. epi;coot. Dis. Afr. 9, 251. WILDING, J. L., KIMBALL, A. VI/ .. WHITAKER, M. W., TRUM, B. F. & RuST, J. H. (1952). Am. ]. vet. Res. 13, sag. WILSON, S. G. (1958). Ann. Rep. Vet. Div. Northern Nigeria, 1957-58, p. 8. WoBESER, G. & GoRDON, M.A. ( r969). Bull. Wildt. Dis. Ass. 5, 31. Streptothricose chez l'ane domestique (Equus asinus asinus). I. Observations cliniques et pathologie clinique (Lloyd) Resume. On decrit les aspects cliniques d'une epidernie de streptothricose chez un groupe d'anes qu'on a observe pendant une periode de cinq mois et demi. Les progres de Ia maladie semblait etre en rapport avec l'hurnidite et les chutes de pluie. Des facteurs comme !'effort n'avaient pas d'effect significatif sur le retablissement de la maladie. Streptothricose beim zahmen Esel (Equus asinus asinus). I. Klinische Beobachtungen und klinische Pathologie (Lloyd) Zusa:nunenfassung. Beschreibung der klinischen Beobachtungen bei einem Ausbruch von Streptothricose in einer Gruppe von Eseln. Die Beobachtungen erstreckten sich tiber fiinfundeinhalb Monate. Das Fortschreiten der Krankheit schien von Feuchtigkeit und von Regen beeinflusst zu sein. Stress hatte keine signifikante Wirkung auf die Genesung. Estreptotricosis en el asno domestico (Equus asinus asinus). I. Observaciones clinicas y patologia clinica (Lloyd) Resunten. Se describen los aspectos clfnicos de una epidemia de estreptotricosis presentada en un grupo de asnos que fueron observados por un perfodo de cinco meses y media. El progreso de Ia enfermedad pareci6 estar relacionado con la humedad y la lluvia. Los factores de stress no tuvieron ninguna significaci6n en el proceso de recuperaci6n de la enfermedad.