Veterinary Research Communications Volume 12 Issue 2-3 1988 [Doi 10.1007_bf00362799] a. R. Bahaman;...

8/10/2019 Veterinary Research Communications Volume 12 Issue 2-3 1988 [Doi 10.1007_bf00362799] a. R. Bahaman; A. L. Ibrahim -- A Review of Leptospirosis in M

1/11

Veterinary Research Communications, 12 (1988) 179-189

Geo Abstracts Ltd, Norwich-printed in England

A REVIEW OF LEPTOSPIROSIS IN MALAYSIA

A. R. BAHAMAN & A. L. IBRAHIM

Faculty of Veterinary Medicine and Animal Science, University Pertanian Malaysia,

43400 Serdang, Selangor, Malaysia

ABSTRACT

Bahaman, A. R . & Ibrahim, A. L., 1988. A review of leptospirosis in Malaysia. Ve?erinary Research

Communicut ions, 12(2-3), 179-189

This paper reviews the literature on leptospirosis in Mala ysia from its first description in 1928 until

the present day. Mo st of the early reports were on investigations of leptospirosis in wildlife and

man and up-to-date, thirty-seven leptospiral serovars from thirteen serogroups have been bac-

teriologically identified. The thirteen serogroups are: Aus trahs, Autum nalis Bataviae , Camc ola,

Cel ledoni, Grippotyphosa, Hebdom adis, Icterohaemorrhagiae, Javanica, Pomona, Pyrogenes,

Sejroe and Tarassovi. Rats have been ascribed as the principal maintenance host of leptospires in

Malaysia. How ever, serovars from the Pomona, Pyrogenes and Sejroe serogroups have yet to be

isolated from rats. I t is considered that the majori ty of leptospirosis cases in man were due to

association of man with an environment where rats were plentiful . Recen t investigations on

dom estic animals disclosed a high prevalence of infection in catt le and pigs and they were

suspected as being the maintenance host for serovar /zur&o and ~ornorru respectively. There is

ample scope for research in leptospiros is, particularly in the epidemiology and control of the

disease in dome stic animals. The strategy to control the infection in dome stic animals and man in

Malaysia is bound to be different from that of the temperate countries, basical ly due to the

presence of a large numbe r of leptospiral serova rs in wiIdh fe, further confounded by geographical

and financial cons traints.

INTRODUCTION

Leptospirosis is recognized as an important zoonosis in Malaysia as well as an impor-

tant animal disease with substantial loss in production. Rats, the principal maintenance

host of leptospirosis, abound in plantations, forests and rural areas and a high incidence is

therefore expected in these areas (Gordon-Smith et ul., 1961). The number of cases of

leptospirosis in humans are apparently under reported and this could be due to oversight

by the medical personnel or to lack of diagnostic facilit ies. Information on leptospiral

infection in domestic animals is lacking and this could impede the understanding of the

epidemiology and the implementation of control programmes of leptospiral infection in

Malaysia. This paper aims to review the historical aspects of leptospirosis in large

domestic animals, cats and dogs and wildlife; to consider the distribution of leptospires in

soils and waters and to discuss the epidemiology of leptospirosis in Malaysia and human

leptospirosis.

HISTORICAL ASPECTS OF LEPTOSPIROSIS IN MALAYSIA

It was not unti l November, 1914 that Inada ef al. (1916) in Kyushu, Japan discovered

the causal organism of Weils disease, a spirochaete, in the liver tissue of a guinea pig

which had been inoculated with blood from a patient suffering from W eils disease. Inada

and his co-workers concluded that the spirochaete was the causal organism of Weils

disease and they named it Spirochaeta icterohaemorrhagiae.

0165-7380/88/ 03.50 0 1988 Geo Abstracts Ltd


2/11

180

Ten years after the discovery of leptospires by Inada and co-workers (1916), Fletcher

(1928) encountered by chance the first case of leptospirosis in Malaysia in April 1925. In

the process of isolating the causal organism of tropical typhus, blood from a patient with

fever of unknown origin was inoculated into guinea pigs. The guinea pigs developed

jaundice, had haemorrhages in the nose and died on the thirteenth day after inoculation.

Postmortem examination revealed signs of leptospirosis. Leptospires were isolated from

the blood, liver and kidneys. Fletcher (1928) was able to diagnose thirty-two cases of

leptospiros is from rubber estate workers and rural inhabitants. It was at this time that

Fletcher (1928), who was then stationed at the Institute of Medical Research, Kuala

Lumpur, introduced Fletchers medium, which is sti ll widely used in many laboratories in

Malaysia and around the world for the isolation of leptospires and, in a semi-solid form,

to maintain these cultures in the laboratory.

Research into the disease leptospirosis therefore had an early start in Malaysia.

Fletchers work created a strong foundation for further research in this field. The

significance of Southeast Asia as an important focus of epidemic and endemic lep-

tospiros is in man and animals was recognized as the result of extensive investigation by

Dutch workers in Indonesia (Walch-Sorgdrager, 1939) and British workers in Malaysia

(Gordon-Smith ef ul., 1961). It is interesting to note that the majority of the currently

recognized distinct antigenic strains of leptospires were first recognized in these two

countries.

LEPTOSPIROSIS IN LARGE DOMESTIC ANIMALS IN MALAYSIA

Detailed studies on leptospirosis in man in Malaysia have been well documented

(Danaraj, 1950; Fletcher, 1928; Robinson & Kennedy, 1956) but studies of the infection

in domestic animals have largely been neglected. A limited serological survey by Wisse-

man etal. (1955) was the earliest attempt to examine the prevalence of leptospiral

infection in domestic animals in Malaysia (Table I). A high prevalence of leptospiral

infection was seen in pigs (3/5) and horses (19/29) in that study. However, the number of

animals examined was too small to make any definitive conclusion regarding the preva-

lence. On the whole, the investigation by Wisseman et ul. (1955) indicated that serovar

hebdurnadis infection was prevalent in most domestic animals.

A similar survey for leptospiral infection in domestic animals was conducted by

Gordon-Smith et ui. (1961). Agglutinating antibodies to leptospires were detected in all

species of domestic animals. Twenty-eight per cent (17/61) of the goats examined were

positive for leptospiral infection whilst cattle had the lowest (4%) prevalence of infection.

Gordon-Smith et ul. (1961) believed that leptospiral infection of man, domestic animals

and probably of all other wild animal species other than rodents were incidental infections

and they concluded that domestic animals did not contribute to the long term mainten-

ance of leptospires in nature.

From the two surveys (Wisseman et ul., 1955; Gordon-Smith et al., 1961) mentioned

above, it was concluded that leptospiros is in domestic animals in Malaysia appeared to be

widespread. The impact of leptospires on the health status and productivity of the animals

has not been studied. Abortions, stillbirths, retained placenta, weak progeny, mastitis

and infertility have all been found to result from leptospiral infection (Ellis et ul., 1985;

Slee et ul., 1983; Songer et ul., 1983; Te Brugge & Dreyer, 1985). There have been no

attempts, however, to investigate the economic impact that leptospirosis may have on

domestic animals in Malaysia. Malaysia i s basically an agriculture-orientated country and

the interest, at that time, was in the production of crops and plants. Leptospirosis in

animals tends to be largely devoid of overt signs of infection and thus does not create any


3/11

181

urgent need for investigation. Programmes to eradicate brucellosis, tuberculosis and a

few other diseases have placed leptospirosis in the background. Many countries have now

been able to eradicate or successfully control these other diseases and the importance of

leptospirosis is slowly being realized.

In one Malaysian study involving ninety buffalo sera from various parts of the country

which were submitted to Professor Liu of the National Taiwan Univers ity, only one

(1.1%) of the sera gave a titre of l/l00 to serovar &~-&z~emo~~~ug~ae (Joseph, 1979).

There are very few reports of leptospiral infection in buffaloes in Malaysia or for that

matter in other parts of the world. The low prevalence of infection in Malaysian buffaloes

is similar to results reported by Hamdy ef ul. (1962) from buffaloes in Egypt. One would

expect a higher prevalence in buffaloes because of their close association with padi fields,

pools and mud. Reports (Carlos et ul., 1970; Sebek ef ul., 1978) from overseas have

indicated a high prevalence of leptospiral infection in buffaloes in some countries. It is

therefore like ly that the low prevalence in Malaysian buffaloes examined by Joseph

(1979) was due to their not being exposed to the infection.

Leong and Maamor (1975) reported a high prevalence of leptospiral infection in the

Kedah-Kelantan calves being brought from Besut, Trengganu to the Institut Haiwan,

Kluang. Nine of the calves developed jaundice and haemoglobinuria fourteen days after

arrival at the Institut. Results of the microscopic agglutination test on twenty-one sera

showed the presence of agglutinins to serovars juvunicu, pyrogenes, cunicolu, pomonu

and turussovi in five animals. However, it was not proven whether the leptospiral infec-

tion was active and responsible for the jaundice and haemoglobinuria seen in the calves.

Arunasalam (1975) examined 163 cattle from M.A.R.D.I., Kluang for the presence of

agglutinating antibodies to leptospires. Fifty (30.7%) of the sera reacted to one or more

of the twelve serovars used as antigens. This high prevalence of infection, however, was

seen in imported breeds of cattle.

A large pig farm in Ipoh in 1971 experienced an abortion storm in one of their sheds.

Sera from eleven aborted sows had titres of l/300 to l/l0000 to leptospiral antigens

(Joseph, 1979). However, no mention was made of the serovars involved. An outbreak of

abortions in sows in Selangor due to icterohuemorrhugiue was reported by Brandenburg

and Too (1981). The diagnosis was based on clinical history and serological examination.

Five of the sows and gil ts that had aborted had a four-fold or more rise in titre but attempts

to isolate leptospires from the aborted foetuses were not successful. From the evidence

collected, the abortions could have been due to any member of the Icterohaemorrhagiae

serogroup, Unless isolates are obtained and identified by the cross-agglutination test, it is

not possible to conclude on the basis of the MAT results alone that the abortions were due

to serovar icterohuemorrhugiue. Attempts to isolate leptospires from livestock in Mal-

aysia have been unsuccessful (Brandenburg & Too, 1981; Joseph, 1979). Isolation of

leptospires from man (Tan, 1970), wildlife (Gordon-Smith er ul., 1961) and soils and

waters (Alexander et ul., 1975), on the other hand, have been very successful. Recently,

Bahaman and Ibrahim (1986) have isolated serovars cunicolu, uwtruZis and juvunicu from

a herd of cattle in Malaysia.

The Regional Veterinary Diagnostic Laboratory, Petaling Jaya has examined abortion

cases seen in gilts in Rasah, Seremban and two of the six urine samples examined by

darkfield microscopy were positive for leptospires. Serological examination of eight

affected sows indicated Bataviae serogroup infection with titres ranging from l/100 to

l/1600. In another investigation, a flock of porkers of about two to three months of age

from a pig farm in Selangor developed skin rashes, irritation and diarrhoea. Histological

examination showed leptospires in renal tubules and the presence of sub-acute interstitial

nephritis (Joseph, 1979). This investigation, however, is not conclusive enough to con-


4/11

182

elude that the clin ical disease was due to leptospirosis. Leptospires could have been

present in the kidneys at the time of an inter-current infection caused by other agents.

A survey of leptospiral infection in pigs from a Penang abattoir was conducted by the

Regional Veterinary Diagnostic Laboratory, Bukit Tengah in 1976. Sections from four of

the thirty-three culled pig kidneys were positive for leptospires by the Warthin-Starry

staining method. The Laboratory also investigated suspected clin ical cases of lep-

tospiros is in 1977 and confirmed the disease in two of the cases by histopathological

examination. Thus, it has been shown that leptospiros is occurs in pigs in Malaysia and is

probably not uncommon. These initial reports of leptospirosis in pigs, highlight the need

to isolate leptospires from affected animals to define the actual serovars causing the

infection. Serovarpomdnu has been reported as the most common serovar affecting pigs

throughout the world (Hathaway ef al., 1981; Michna, 1970) but much of the work with

pigs has been carried out in temperate countries and the results cannot necessarily be

extrapolated to a tropical country such as Malaysia.

From 1975 to 1978, the Veterinary Research Institute, Ipoh examined 615 sera from

domestic animals and a further thirteen from i ts staff. Some of the sera were obtained

from animals suspected of having clinical leptospirosis (Joseph, 1979). The results from

this study differed from that of Gordon-Smith et ul. (1961). In the Ipoh study, cattle were

shown to have the highest (35.3%) prevalence of leptospiral infection in contrast to

Gordon-Smiths results where only 3.8% of cattle were positive (Table I). Agglutinins to

thirteen leptospiral serogroups were detected in the cattle tested, the three most impor-

tant serogroups observed being Hebdomadis, Tarassovi and Pomona. Pigs demonstrated

agglutinins to six leptospiral serogroups with serogroups>Bataviae, Ballum and Ict-

erohaemorrhagiae being the most common.

It appears that domestic animals in Malaysia are exposed to a large number of

leptospiral serovars. Thirty-eight serovars have been isolated from man and animals in

Malaysia (Alexander et ul., 1957; Bahaman & Ibrahim, 1986; Gordon-Smith et uZ., 1961;

Tan, 1964). There is therefore a need to determine which serovars are maintained

exclusive ly in domestic animals and the proportion which are accidenta l infections

resulting from contact with an environment contaminated with leptospires from wildlife

sources. Each future isolate wil l have to be carefully identified and in this respect the

bacterial restriction endonuclease DNA analysis (BRENDA) technique wil l be a very

useful procedure to identify and verify isolates. It has been shown to be able to differen-

tiate strains within serovars (Marshall ef ul., 1981; Robinson eful., 1982). How the

isolates were identified in the earlier studies was not clearly described. Differentiation of

serovars within a serogroup by cross-agglutination absorption is difficult as all are anti-

genitally close ly related and many share common major antigens (Manev, 1976).

LEPTOSPIROSIS IN DOGS AND CATS IN MALAYSIA

Fletcher (1928) was the first to report the presence of leptospirosis in dogs in Malaysia.

The leptospiral isolate obtained by Fletcher (1928) was identified as serovar hebdomudis.

In 1927, Symonds, the veterinary officer in Kuala Lumpur noticed that a number of young

dogs were dying with either jaundice or just haemorrhages. From one of these dogs, a

leptospiral strain was isolated which proved to be pathogenic for guinea pigs and dogs.

According to Fletcher (1928), the isolate was not serovar icferohaemorrhagiue but was

identified as serovar

hebdomadis.

At present, two types of leptospiros is are suspected in

dogs in Malaysia. One type which manifests itself as aundice is found in young dogs and is

generally assumed to be caused by serovar icterohaemorrhagiae whilst the other, where

there is an absence of jaundice, is seen in older dogs and is generally caused by serovar


5/11

183

canicola. These two serovars have been recognized as the cause of canine leptospirosis

throughout the world (Michna, 1970; Sullivan, 1974). According to Sullivan (1974), dogs

often acquire serovar icterohaemorrhagiae infection from carrier rats, whereas transmis-

sion of serovar canicola is direct from dog to dog via contaminated urine. Both of these

serovars have been isolated from rats in Malaysia (Gordon-Smith et al., 1961). So there is

a possibility that the epidemiology in Malaysia may be different from that described by

Sullivan (1974) and that rats could be a source of infection for dogs with both serovars. On

a world wide basis, canicola is the most common serovar infecting dogs and in many parts

of the world dogs act as a maintenance host and as such can be a source of infection to

other dogs, domestic animals and man.

The sera of dogs and cats examined by Gordon-Smith et al. (1961) were obtained from

animals around abattoirs or other parts of Malaysia by veterinarians. Only one positive

culture was obtained and it was identified as serovarpomona (Gordon-Smith et al., 1961).

Sero logical examination indicated that 18% of the dogs and 10% of the cats had lep-

tospiral infection.

A survey of animals in Malaysia revealed that the prevalence in dogs was the second

highest (42%) in domestic species after pigs (Table I) (Wisseman et al., 1955). Five of

nine dogs submitted to the Veterinary Research Institute, Ipoh had positive titres to

leptospirosis. However, the serovar identifications were not disclosed. Two of the dogs

that died were autopsied and the histopathological findings of haemorrhagic gastro-

enteritis and acute interstitial nephritis were suggestive of an acute leptospirosis. Both

cases, however, failed to provide a positive culture. In another incidence, one of three

dogs kept on a pig farm where leptospirosis was suspected was found to be in poor bodily

condition, lethargic and jaundiced and had l/l00 titres to bataviae andgrippotyphosa and

l/400 titres to cynopteri and canicola (Joseph, 1979). Again, no culture of an infecting

leptospire was achieved and the possibi lity that this may have been a case of leptospirosis

can only be surmised.

Shophet (1979) reported that leptospiral infections are not commonly seen in cats in

New Zealand and, if they do occur, they are like ly to be subclin ical. Both Harkness et al.

(1970) in New Zealand and Gordon-Smith et al. (1961) in Malaysia isolated serovar

Pomona from cats which were clin ical ly normal but where interstitial nephritis was

evident at autopsy.

TABLE I

Serological prevalence of leptospiral infection in domestic animals in Malaysia

Wisseman et al. Gordon-Smith er aZ. Joseph

(1955) (1961) (1979)

No offsera No. ofsera No. ofsera No. ofsera No. ofsera No. ofsera

examined positive examined positive examined positive

Cattle

Buffaloes

Pigs

Sheep

Goats

Dogs

Cats

Horses

98 21 (21.4)

7 1 (14.0)

5 ; E]

13

2 (li4)

19 8 (42.1)

Not available

29 19 (65.5)

52 2 (3.8)

34 5 (14.7)

45 5

(11.1)

Not available

61 17 (27.9)

495 175 (35.3)

Not available

52 12 (23.1)

206 i (7.7)

9 5 (56.6)

Not available

13 2 (15.4)

( ) = Percentage of sera positive.


6/11

184

Malaysia has a large number of stray dogs and cats and it would be interesting to find

out whether these stray animals have an important role to play in the epidemiology of

leptospiral infection in this country. They have the potential to act as an important source

of leptospiral infection for man and other animals.

LEPTOSPIROSIS IN WILDLIFE IN MALAYSIA

In addition to detecting leptospires in man and dogs, Fletcher (1928) also managed to

isolate leptospires from rats. Fletcher observed that healthy rats were often carriers of

leptospiros is and that the leptospires detected were often seen in the kidneys and urine.

Twenty-six percent of the black rats (ZZurlw rut&~) examined by Fletcher (1928) were

found to have leptospires. The majority of the leptospires isolated from these rats belong

to serovar hebdomadis. Serovar icterohaemorrhagiae was not detected from any of the

rats.

As a result of frequent reports of leptospiros is in military personnel during jungle

operations, attention was focussed on forest and scrub as an important ecosystem for

leptospiral infection. Wisseman etuZ. (1955) found that three species of Malaysian

rodents had evidence of leptospiral infections. The leptospiral serovars isolated from

these rats were mainly from serogroups Hebdomadis, Grippotyphosa and Canicola. A

low prevalence of leptospiral infection was observed in the town rat, R&us ruttw diurdii.

The only leptospiral isolate obtained from rats in Sabah (then known as North Borneo)

was a member of the Icterohaemorrhagiae serogroup. It was cultured from Rattus

whiteheudi, another rodent species inhabiting forest areas.

Gordon-Smith et ~1, (1961) made a detailed study of leptospirosis in rats, mice and a

few other species of wildlife in Selangor. Most of the leptospires isolated were from rats

(32%) while a few isolates were obtained from palm civets and bats. These workers

managed to culture 104 leptospiral isolates from wildlife. The majority (15/23) of the

isolates from the Icterohaemorrhagiae serogroup were obtained from house rats, R&us

norvegicus, whilst most (37/42) of the strains from the Javanica serogroup were isolated

from Rattus argentiventer found in ricefields. Serovar Pomona, on the other hand, was

isolated from a domestic cat and palm civets found in towns and villages.

House-infesting animals

Rat&s norvegicus, which has a very limited distribution and is found mainly around

ports, accounts for 80% of the house-infesting rats with evidence of leptospirosis. No

evidence of infection was found in the house mouse, Mus musculus. Other house-

infesting animals are the shrew, Suneus murinus, with an infection rate of 5% and the

palm civet, Paradoxurus hermaphroditus with a prevalence of infection of 19% (Gordon-

Smith et ul., 1961).

Animals of scrub and cultivation

Among the rats inhabiting scrub and cultivated land, Rattus jalorensis had the lowest

prevalence (3%) of infection as judged by the presence of positive titres. It is found in

scrubs, gardens, rubber and oil palm estates. Rattus exulans, common in scrubs, grassland

and forest fringe, had a prevalence of infection of 7%. The highest prevalence, however,

was seen in Rattus argentiventer that inhabits grasslands and ricefields. Two species of tree

squirrels, Caffoseittrus caniceps and C. notatus, are common in gardens, estates and


7/11

185

coconut plantations. Only one (l/178) of the squirre ls examined had evidence of

infection.

Forest animals

A small number of terrestrial forest animals were sampled. Evidence of infection was

observed in the mouse deer (Tragulus sp.), porcupines (Atherrurus macrourus) as well as

some bats and reptiles. A high (13/17) prevalence of agglutinating antibodies to lep-

tospiral infection was seen in aquatic fish-eating snakes, Acrochordus javanica. On the

other hand, no evidence of infection is seen in nonhuman primates (Gordon-Smith

et al . ,

1961).

LEPTOSPIRES FOUND IN MALAYSIAN WATERS AND SOILS

Fletcher (1928) was successful in isolating leptospires from streams and ponds in

Malaysia. The leptospiral isolates obtained were of questionable pathogenicity since the

leptospires could not be recovered from the blood or organs of guinea pigs after experi-

mental infection. In Sumatra, Sardjito and Zueler (1928), using similar culture tech-

nique, were able to recover leptospires from ponds and running streams. The presence of

these leptospires was associated with leptospirosis in the regions. However, information

on the pathogenicity of the isolates were not presented.

Workers from several countries have reported the isolation of leptospires from various

sources of water (Appelman, 1934). Baker and Baker (1970) in I&ala Lumpur developed

a screening method for the isolation of leptospires from waters and soils by inoculating

samples into hamsters. The pathogenicity of the isolates was indicated by death of the

hamsters. Out of 13 850 hamsters, 1415 died within twenty days of inoculation.

Altogether 366 leptospiral isolates were obtained. Soi l and water samples obtained

around Kuala Lumpur from 1961 to 1962 were positive for leptospires. Altogether

thirteen leptospiral serogroups were identified, including those that have been found

infectious for man in Malaysia (Alexander

et al . ,

1975). Not a ll pathogenic serovars are

fatal for hamsters, hardjoprajitno being one example. So this technique wil l have failed to

take these into account (R. B . Marshall, New Zealand, personal communication).

THE EPIDEMIOLOGY OF LEPTOSPIRAL INFECTIONS IN MALAYSIA

Evidence of leptospiral infection has been found in a wide variety of animals in

Malaysia. Gordon-Smith et al. (1961) reported that the natural maintenance host of

leptospires in Malaysia appeared to be mainly or entirely rats. Infections of man and

domestic animals were therefore thought to be incidental infections which do not contrib-

ute to the long term maintenance of leptospires in nature. However, it is now known that

domestic animals may harbour leptospires for quite long periods and so may act as

important maintenance hosts. Transmission of infection is usually through contaminated

water although direct urinary contamination may occur in certain circumstances. In

towns, human infections were probably from the house rat, which, although having a low

excretion rate, is numerous and in close contact with man (Gordon-Smith et aZ. , 1961).

Leptospirosis has been close ly associated with agricultural occupation. One of the most

important occupations is rice cultivation. The majority of the cases reported in Asia were

from ricefields (Babudieri, 1957; Brewer et aZ. , 1960). The prevalence of the disease is

expected to be correspondingly high amongst the padi planters in Malaysia. However, an

appraisal of clinical leptospirosis in Malaysia by Tan (1970) showed that, amongst


8/11

186

fourteen occupational groups examined, padi planters represented only 1.4% of the total

positive cases. This was by no means one of the most frequently encountered groups with

clin ical leptospirosis. It is not clear why padi planters, who are in close contact with highly

infected Rattzu argentiventer, do not become infected. As many leptospiral infections are

subcl inical and are only detectable by serology, it is possible that padi planters are in fact

highly susceptible but are not detected clin ically by medical personnel. It has been

suggested by Tan (1970) that the low frequency of clinical leptospirosis in padi planters

was probably due to acquired immunity and also possibly to conditions in the ricefields,

which may be unfavourable for the growth and multiplication of leptospires. Gordon-

Smith and Turner (1961) studied in the laboratory the effect of pH on the survival of

leptospires in water and found that leptospires survived longer in alkaline than in acid

water. These workers observed that the water and soil of the ricefields in Malaysia have

low pH values which may be responsible for the low incidence of infection (Gordon-

Smith & Turner, 1961).

The large number of cases among the rubber estate workers is not easily explained. The

rodent species prevailing in rubber estates is mainly Rattus jalorensis which has been

found to have a low leptospiral prevalence. Forest areas in which highly infected rats

abound may have served as a source of leptospirosis to rubber estates closely adjacent to

them. The commensal house rats, many of which were infected with leptospires, were

probably another source of infection. Baker (unpublished data) showed that most mining

pools in Malaysia were only infrequently contaminated with leptospires. This could

possibly account for the low prevalence of clin ical cases among tin miners.

LEPTOSPIROSIS IN MAN IN MALAYSIA

Most of the early work on leptospirosis in Malaysia were investigations of the disease in

man. The recognition of leptospirosis in Malaysia began in 1925 by Fletcher (1928) who

reported a fatal case in a man due to Leptospira icterohaemorrhagiae. During this early

period, Fletcher (1928) was able to identify serovars icterohaemorrhagiae, hebdomadis

and pyrogenes from twenty-one patients.

In 1927, Kanagarayer while working with Fletcher, demonstrated leptospires in four

out of five successive cases rom Kuala Lumpur General Hospital and, at almost the same

time, Galloway (1926) detected four cases of leptospirosis in Singapore (then part of

Malaysia). More investigations on leptospirosis were reported following these early

reports (Ryrie, 1930). Since then, the disease has been recognized with increasing

frequency throughout the country (Wisseman et al., 1955). It was felt that while typical

cases with jaundice were recognized, many of the mild anicteric cases escape recognition.

However, meningitic leptospirosis has not been reported in Malaysia proper (Danaraj,

1950).

It became apparent that leptospires were a frequent cause of febrile illness among

military personnel and civi lians in Malaysia and this revived interest in leptospiros is

research (Broom, 1953). Robinson and Kennedy (1956) described thirty-one cases of

leptospirosis among British army personnel in 1953. Twenty-nine were proven to be

leptospirosis. In another study, McCrumb et al. (1957) examined 614 military personnel

and 238 civil ians suffering from febrile illness. Leptospirosis was found to be the major

cause, accounting for 35% of the military cases and 13% of the civil ian cases. Alexander

et al. (1957) identified thirty pathogenic leptospiral serovars from military and civi lian

cases n Malaysia from 1953 to 1955. The significance of leptospirosis as a major cause of

febrile diseases amongst civ ilian and military personnel in Malaysia was therefore

established.


9/11

187

Danaraj (1950) reviewed nineteen cases of leptospirosis seen in humans in Singapore.

Thirteen were anicteric whilst seven had evidence of meningeal involvement. These were

the first cases of meningitic leptospiros is recorded in Malaysia. Danaraj (1950) felt that

meningitic leptospirosis may be fairly common in the country but the absence of jaundice

has led to the diagnosis being overlooked. Tan (1964) similarly reported that the clin ical

manifestations of leptospiros is in Malaysia were often mild or moderate. Tan (1964)

believed that leptospirosis is much more common in Malaysia than is generally realized.

She pointed out that many cases of leptospirosis escaped recognition either because the

clin ical features do not conform with the generally expected picture of Weil s disease or

because clinicians failed to consider it in the differential diagnosis of pyrexial illness.

According to Tan (1964), leptospirosis can be mild and may be subcl inical and therefore

deceptive.

It is apparent that leptospiros is is endemic and widespread in Malaysia (Ungku Omar-

Ahmad, 1967). Surveys in humans have shown a high prevalence of antibodies to

leptospires throughout Malaysia. The highest distribution was found among labourers

working in rubber estates and those dealing with sewage, drainage, forestry, town

cleaning and anti-malarial work. Contrary to expectations, veterinarians, farmers, abat-

toir workers and people handling livestock or animals did not appear to be frequently

affected. Isolation of leptospires from human cases showed that the important serovars

were pyrogenes, autumnalis, icterohaemorrhagiae, canicola and hebdomadis. In a more

recent study, Tan (1970) examined 1993 suspected human casesof leptospirosis and found

28% of the cases were positive. Leptospires were successfully isolated from thirty-four

cases. Twenty-eight of the isolates have been identified: nine were identified as serovar

pyrogenes, five as serovar canicola, three as serovar hebdomadis and two each as serovar

icterohaemorrhagiae, serovar Pomona and serovar grippotyphosa.

CONCLUSION

This review is an attempt to produce an overall account of leptospirosis in Malaysia.

The first report by Fletcher (1928) provided a detailed description of the disease as seen in

the tropics and is the foundation for further studies in this field in this country. Subsequent

investigations mainly from the Institute of Medical Research, Kuala Lumpur were on the

description and diagnosis of the disease, particularly from the humans and wildlife

aspects. Joseph (1979) briefly reviewed the disease in domestic animals. Abortions in

animals and pyrexia of unknown origin (PUO) in civil ians were frequently reported and

some were suspected to be due to leptospirosis. The vast number of leptospiral serovars

that have been reported in the country, the abundance of wildlife and the conducive

climate and environment would generate ample materials for research in this field.

Investigations on the economic, epidemiology and public health aspects of the disease are

lacking and therefore warrant further investigation. It is postulated that the epidemiology

of the disease in this country is different from those reported in temperate countries. It is

evident that the incidence of infection is mainly due to intrusion of man into forest areas

or migration of wildlife, particularly rats to human dwellings and plantations. Currently,

domestic animals do not appear to play a major role in the epidemiology of the infection,

but this may be slowly changing as the animal industry in Malaysia develops and more

sophisticated and intensive farming is being organized.


10/11

REFERENCES

Alexander, A. D., Evans, L. B., Baker, M . F., E&son, D. & Marriapan, M. , 1975. Pathogenic

leptospires isolated from Malaysian surface waters. Apphed Microbiology, 29, 3@-3

Alexander, A. D. , Evans, L. B. , Toussant , A. J . , Marchwick i , R. H. & McCrum b, F. R. , 1957.

Leptosp irosis in Ma laya. II. Antigenic analysis of 110 leptospiral strains and other serologic

studie s. Ame rican Journal of Tropical Medicine and Hyg iene, 6, 871-89

Appelman, J. M. , 1934. Isolation of L. icterohemorrhagiae from water. A contribution to the

epidemiology of Weil s disease. Leeuwenhoek ned Ti ja%chr., 1,22-6

Arunas alam, V., 1975. Leptospiral antibodies in the sera of cattle . Malay sian Veterinary Jou rnal, 6,

14-17

Babudieri, B., 1957. Leptospirae and leptospirosis in Italy. Science and Med icine, Ztalinia, 5,658-

702

Bahaman, A. R. & Ibrahim, A. L., 1986. A serological and bacteriological study of leptospiral

infection in a cattle herd in Ma laysia. Veterinary Rec ord, 119, 325-6

Baker, M. F. & Baker, H. J., 1970. Pathogenic Leptospira in Malaysian surface waters. American

Journal of Tropical Med icine and Hyg iene, 19, 485-92

Bradenburg, A. C. & Too, H. L., 1981. Abort ions in swine due to Leptospira icterohemorrhagiae.

Kajian Veterinar, 13, 15-17

Brewer, W . E., Alexander, A. D., Hakioglu, F. & Evans, L. B., 1960. Rice f ield leptospirosis in

Turkey . A serological survey. American Journal of Tropical M edicine and Hygiene, 9, 22939

Broom, J. C., 1953. Leptospirosis in tropical countries. A review. Transactions of the Royal Society

of Tropical Medicine and Hyg iene, 47, 273-91

Car los, E. R. , Kundin, W. D. , Tsai , C. C. , I rv ing, G. S. , Watten, R. H. & Batungbakal, C. , 1970.

Leptosp irosis in the Philippines: 2. Serologic studie s. Acta Med ica Philippina, 6, 154-9

Danaraj, T. J., 1950. Leptospirosis. Proceedings of the Alumni Association of King Edward VII

College of Med icine. SineaD ore. 3. 326-39

Ell is, WY A.: OBrienJ. J.: Bryson,D. G. & Mac kie, D. P., 1925. Bovine leptospirosis: Some

clinical features of serovar hardio infection. Veterinarv Rec ord. 117. 101-4

Fletcher, W ., 1928. Recen t wo rk on leptospirosis, tsutsugamush i disease and tropical typhus in the

Federated Malay States.

Transactions of the Royal S ociety of Tropical Medicine and Hygiene, 21,

265-88

Galloway, D. J., 1926. Epidemic jaundice (Leptospira icterohemorrhagiae). Malayan Medical

Journal, 1, l-5

Gordon-Smith, C. E. &Turner, L. H., 1961. The effect of pH on the survival o f leptospires in water.

Bulletin of World Health O rganisation. 24. 35-43

Gordon-Smiih, C. E., Turner, c H. , Harrisson, J. L. & Broom, J. C. , 1961. Animal leptospirosis in

Malaya. 1. Method s, zoogeographical background and broad analysis of results. Bul let in ofthe

World Hea lth Organisation, 24, 5-21

Ham dy, A. H., Brownlow, W . J. & Dedeaux, J. D., 1962. Leptospirosis in bovines and their human

contac ts in Egypt (U.A .R.). American Journal of Tropical Medicine and Hygiene, 11, 98-101

Harkne ss, A. C., Smith, B. L. & Fowler, G. F., 1970. An isolation of Leptospira serotypepomona

from a dome stic cat. New Zealand Veterinary Journal, 18, 175-6

Hathaw ay, S. C. , Li t t le, T. W . A. & Stevens, A. E., 1981. Serological and bacteriological survey of

leptospiral infection in pigs in southern England. Res earch in Veterinary Scien ce, 31, 169-73

Inada, R., Ido, Y ., Hoki, R., Kaneko, R. & Ito, H., 1916. The etiology mode of infection and

spe cific therapy of We ils disease (Spirochae tosis icterohaem orrhagica). Journal of Experi-

mental Medicine, 23, 377-402

Joseph, P. G., 1979. Leptospirosis in animals in We st Malaysia. Malaysian Journal of Pathology, 2,

15-21

Leong, Y. K. & Maam or, H. A., 1975. Leptospira agglutinins in Kedah/Kelantan type calves.

Kajian Veterinar, 2, 67-8

Mane v, C ., 1976. Serological characterist ics of the Leptospira serogroup Pomona. I. Factor an alysis

of the reference strains . II . Cha nges in the agglutination and absorption properties of the

reference strains after formalin and heat-inactivation . Zentralblatt fur Bakteriologie, Parasit-

tenkun de, Infektionskran kheiten und Hyg iene. Erste Abteilung Originale, 2 36, 316-27

Marshal l , R. B., Wil ton, B. E. & Robinson, A. J., 1981. Identi fication of Leptospira serovars by

restriction endonuclease analy sis. Journal of Med ical Microbiolog y, 14, 562-9

McCrum b, F. R. , Stockard, J . L. , Robinson, C. R. , Turner, L. H. , Lev is , G. , Maisey, C. W.,

Kel leher, M. F., Gleiser, C. A. & Smadel, J. E., 1957. Leptospirosis in Malaya. I. Sporadic ca ses


11/11

189

among military and civil ian personnel. America n Journal of Tropical Medic ine & Hygiene, 6,

238-56

Michna, S. W ., 1970. Leptospirosis. Veterinary Record, 86,484-96

Robinson, C. R. & Kennedy, H. F., 1956. An investigation into cl inical and laboratory features of

outbreak of 31 cases of anicteric leptospirosis.

Journal

of

the Royal Army Medic al Corps,

102,

196206

Robinson, A. J., Ram adass, P., Lee, A. & Marshal l , R. B., 1982. Differentiat ion of subtypes within

Leptospira interrogans serovars hardjo, balcanica and tarassovi, by bacterial restriction-endo-

nuclease DNA analys is (BRENDA). Journal of Medical Microbiology, 15, 331-8

Ryrie, C. A., 1930. Concurrent leptospirosis and schistosom iasis in Malaya; case. Malayan Medical

JournaZ, 5, 148-50

Sardj ito, M. & Zueler, M. , 1928. A further study of the biology of Spirochaeta bif7exa syn.

Leptospira icterohernorrhagiae syn. S. icterogenes in the tropics. Meded. Dienst. d. Vol-

ksgezondheid in Nederl. btd ie, 17,535-44

Sebek, Z. , Blazek, K., Valova, M. & Amin, A., 1978. Further results of serological examination of

dome stic animals for leptospirosis in Afghanistan. Poha ParasitoIogica, (Praha), 25, 17-22

Shophet, R., 1979. A serological surve y of leptospirosis in ca ts. New Zealand Veterinary Journal,

27, 236-45

Slee, K. J., McO rist, S. & Ski lbeck, N. W ., 1983. Bovine abortion associated with

Leptospira

interrogans serovar hardjo infection. Australian Veterinary Journal, 60, 204-6

Songer, J. G., C hi lel l i, C. J., Marshal l , N. M., Noon, T. H. & Meyer, R., 1983. Serologic survey for

leptospirosis in Arizona beef cattle in 1981. American Journal of Veterinary Research, 44,1763-4

Sull ivan, N. D. , 1974. Leptospirosis in animals and man. Austrahan Veterinary Journal, SO, 216-23

Tan, D. S K., 1964. The importance of leptospirosis in Malaya. Malayan Journal of Medicine, 18,

164-71

Tan, D. S. K., 1970. Cl inical leptospirosisin We st Malaysia (1958-1968). Southeast Asian Journalof

Tropical Medicine and Public Health, 1, 102-11

Te Brugge, L. A, & Dreyer, T., 1985. Leptospira interrogans serovar hardjo associated with bovine

abortion in South A frica. Onderstepoort Journal of Veterinary Research, 52, 51-2

Ungku Om ar-Ahmad, 1967. Veterinary publ ic health with part icular reference to Malaysia. Kajian

Veteriniare , 1, 54-62

Walch-So rgdrager, B., 1939. Strains of Leptospira and disease caused b y them . Geneesk. Tijdschr.

v. Neder.-lndie , 79, 3077-90

Wissem an, C. L., Traub, R. , Gochenour, W . S., Smadel, J . E. & Lancaster, W . E., 1955.

Leptosp irosis of man and animals in urban, rural and jungle areas of south east Asia. American

Journal of Tropical Medicine and Hygiene 4, 2940

(Accepted: 21 July 1987)

Veterinary Research Communications Volume 12 Issue 2-3 1988 [Doi 10.1007_bf00362799] a. R. Bahaman;...

Documents

Transcript of Veterinary Research Communications Volume 12 Issue 2-3 1988 [Doi 10.1007_bf00362799] a. R. Bahaman;...