Rev. sci. tech. Off. int. Epiz., 1996, 15 (1), 155-169

Husbandry and diseases of camelids M.E. F O W L E R *

Summary: Camels of the Old World and the New World have provided the indigenous human population with meat, milk, fibre and fuel, also serving as beasts of burden to carry loads, for millennia. With the advent of motorized vehicles, the use of camelids became obsolete except in isolated situations. The numbers of camelids diminished dramatically. A reversal of that trend is now occurring, with a recognition that these animals still function in their respective environments better than any other species of livestock Camelids have always been popular animals in zoos. Camels and two of the South American camelids are domestic animals which adapt well to contained management. They have a unique ability to obtain nourishment from harsh forages. Their reproductive physiology is different from that of any other livestock species.

Few diseases of camelids are restricted to these species, and camelids do not serve as a reservoir for any of the major diseases of livestock

KEYWORDS: Alpacas - Camels - Dromedaries - Guanacos - Infection - Llamas - Parasitism - Vicuñas - Wildlife.

I N T R O D U C T I O N

Camelids have served the needs of people for thousands of years. They have provided food (meat, milk), fibre and fuel, and served as beasts of burden, as well as being important in religious and secular ceremonies both in ancient civilizations and to this day. The industrial revolution minimized the value of camelids and numbers declined; but recently there has been a renaissance in both Old and New World camelids. Once again, camelids are of value in their native lands, as well as in North America, Europe and Australia (8).

An important concept to understand when dealing with camelids is that taxonomically they are not ruminants, nor do they share many of the ruminant diseases which are so important in livestock disease epidemiology (Table I). The family Camelidae is classified in the order Artiodactyla, suborder Tylopoda. The Old World species are the bactrian camel (Camelus bactrianus) and the dromedary (C. dromedarius). New World species are the llama (Lama glama), alpaca (L. pacos), guanaco (L. guanicoe) and vicuña (Vicugna vicugna) (8, 18). Camelids evolved in North America, with primitive progenitors dating back approximately 40 million years to the Eocene epoch. At this early date, all Artiodactyla were single-stomached animals. The Tylopoda and Ruminantia then separated to follow different evolutionary

* Professor Emeri tus, Depar tment of Medicine and Epidemiology, School of Veterinary Medicine, University of California-Davis, 427 Cabrillo Avenue, Davis , C A 95616-8737, United States of Amer ica .

156

pathways. Eventually, the Old World camel progenitors migrated westward to Asia, crossing a land bridge over the Bering Straits at a time when glaciation lowered the sea level, and eventually declining to extinction in the Americas. New World camelid progenitors migrated south across the newly-formed Caribbean land bridge (8, 18).

TABLE I

Differences between South American camelids and ruminants Evolutionary pathways diverged 40 million years ago

Parameter South American camelids Ruminants

Blood Red blood cells elliptical and small Red blood cells round and larger (6.5 µ); predominant white blood (10 µ); predominant white blood cell is neutrophil; leukocytes up to cell is lymphocyte; leukocytes up to 22,000/µl 12,000/µl

Foot Toenails and soft pad; second and Hooves and sole; second and third third foot bones horizontal foot bones vertical

Digestive system Parallel evolution: foregut As for camelids fermenter; regurgitation, re-chewing and re-swallowing

Stomach Three compartments, resistant to Four compartments, susceptible to bloat bloat

Dental formula I: 1/3, C: 1/1, PM: 1-2/1-2, I: 0/3, C: 0/1, PM: 3/3, M: 3 / 3 x 2 = 28-30 M: 3 / 3 x 2 = 32

Reproduction Induced ovulation Spontaneous ovulation No oestrous cycle Oestrous cycle Follicular wave cycle No follicular wave cycle Copulation in prone position Copulation in standing position Placenta diffuse Placenta cotyledonary Epidermal membrane surrounding No epidermal membrane on fetus fetus Cartilaginous projection on tip of No cartilaginous projection on tip penis of penis Ejaculation prolonged Ejaculation short and intense

Respiratory system Soft palate elongated; primarily Soft palate short; nasal or mouth nasal breathing breathing

Urinary system Kidney smooth and elliptical Kidney smooth or lobed Suburethral diverticulum in female No suburethral diverticulum

Parasites Unique lice and coccidia; Do not share lice or coccidia with gastrointestinal nematodes shared cattle, sheep and goats, but do share with cattle, sheep and goats gastrointestinal nematodes

Susceptibility to Minimally susceptible to Highly susceptible to tuberculosis, infectious diseases tuberculosis; no known natural bovine brucellosis, and foot and

bovine brucellosis; mild mouth disease susceptibility to foot and mouth disease; no clinical disease with most other bovine viral diseases

I: incisors C: canines PM: premolars M: molars

157

The precise time and location of domestication of the bactrian camel is unknown, but this is thought to have occurred some time prior to 2500 BC on the borders of the Caspian Sea. Domestication of the dromedary had occurred earlier, prior to 3000 BC in the Arabian peninsula. The cradle of llama domestication is in the Andean highlands, probably around Lake Titicaca, in approximately 4000 BC. Alpaca domestication probably took place elsewhere in Peru at about the same time (18).

Camels were essential to the Bedouins of the Arabian peninsula and North Africa. Bactrian camels carried goods along the old Silk Route to China. Camels were also cavalry mounts until Europeans introduced the horse. Ultimately, motorized trucks supplanted camels as freight carriers. Camels had all but become mere curiosities in zoos until two decades ago, when serious interest revived in these marvellous animals which are so well-adapted to the harsh environmental conditions of the desert.

A few wild bactrian camels still roam the steppes of the Gobi desert in Mongolia, but essentially all camels are now the product of domestication. In South America, the vicuña and guanaco remain wild species, while the llama and alpaca are domesticated. The evolution of both Old and New World species - and their accompanying infectious and parasitic disease agents - occurred in geographical regions separated from the habitats of domestic ruminants. Table I lists differences between camelids and ruminants.

H U S B A N D R Y PRACTICES

Old World camels inhabited some of the most inhospitable areas of the world: the bactrian camel in the high deserts of Asia, and the dromedary in the hot dry deserts of the Middle East. Camels are famous for their ability to subsist on harsh, dry and sparse vegetation, at least for a time. The hump(s) of a camel provide(s) a good indication of the nutritional status of the animal. The hump consists of fat interspersed with fibrous tissue. During periods of poor energy intake, the camel is capable of metabolizing the fat in the hump, which shrinks as a result. The humps of the bactrian camel are usually more peaked than the hump of the dromedary, and when the animal loses weight the humps flop over to one side. Floppy humps caused by starvation should not be confused with the congenital floppy humps which may be seen in certain well-conditioned camels (6, 8).

Racing of dromedary camels has become a popular pastime in a number of Middle Eastern countries. Camels in training are kept in outdoor enclosures, sometimes with shade provided. Feeding practices are extremely varied, from browsing in the desert to feeding upon freshly-cut alfalfa and concentrate supplements. Dates and milk are fed to racing dromedaries. The rationale for feeding milk escapes this author. Some sheikhs have pioneered in the nutrition and feeding of camels, and have imported European nutritionists to study nutrition and manage rations. Feed mills have been constructed, and complete diet pellets have been formulated.

Camels may be purged prior to a race; the rationale is to empty the stomach to prevent its bulk from interfering with the camel while running. Some desert shrubs are known to have a cathartic effect and, prior to a race, the alfalfa in the diet is substituted by a purgative plant. The purgative action produces projectile diarrhoea, thus depriving the camel of nourishment and, more seriously, water.

158

In zoos, camelids are maintained in a wide variety of enclosures. In general, the only common requirements are that there be sufficient space to move about, shade, shelter from inclement weather, and water for drinking (9). Some zoos provide ponds for bathing. Hay of various types is the primary forage. On facilities with large acreages, camelids may obtain most of their nourishment from pastures. Only rarely is it necessary to supplement the diet with concentrates (6). Camelids may be affected by deficiencies of such nutrients as selenium, vitamin E, copper and zinc. Mineral supplements should be supplied in a granular form, as camelids do not readily chew or lick mineral blocks.

DISEASES

Infections (8, 17)

The prevalence of viral diseases in camelids is unknown. Few clinically-important viral diseases have been described (Table II). The results of serological surveys indicate that camelids are exposed to and respond immunologically to numerous viral agents, without developing clinical disease. With the increased importance of camelids, more attention is being paid to specific diseases. Whether or not camelids are susceptible to a number of important viral diseases of cattle and sheep is unknown at present (8). Rinderpest has not been reported in South American camelids, but neither does the virus occur in South America; to the knowledge of the author, no one has yet experimentally challenged South American camelids with the rinderpest virus. Camels are known to be mildly susceptible to rinderpest infection, and there is reason to believe that all members of the order Artiodactyla are susceptible to this virus, at least to some degree.

Herpesviruses are highly evolved, and are usually well-adapted to one or more hosts. Interestingly, no herpesviruses unique to camelids have been identified. When herpesviruses infect a non-adapted host, serious disease or death is likely to result, which has occurred in both llamas and alpacas infected with equine herpesvirus type 1 (EHV-1). The clinical syndrome is characterized by blindness (caused by retinal degeneration) and encephalitis (14).

Three proliferative infections of the skin of camels are camelpox (Orthopoxvirus), camel contagious ecthyma (Parapoxvirus) and papillomatosis (Papillomavirus) (13, 17). Of these, camelpox is the most widespread, severe and debilitating disease, causing high mortality in young camels. A new vaccine is currently being used to minimize the effects of the infection (17).

Fungal and bacterial diseases of camelids are listed in Table III. The major clostridial diseases of domestic animals and humans are ubiquitous and would be serious threats to livestock production if vaccines were not available. Camelids acquire some of these diseases, and in some cases the diseases have had a serious impact on a herd. Clostridium perfringens types C and D are found throughout the world and may pose problems at the regional level. C. perfringens type A produces a distinct disease in racing camels and high mortality in neonatal camelids in South America (8).

159

TA

BL

E

II

Vir

al d

isea

ses

of

cam

elid

s

Susc

eptib

ility

Dis

ease

nam

e in

Eng

lish

Oth

er l

angu

age

equi

vale

nts

Org

anis

m

Synd

rom

e C

amel

So

uth

Am

eric

an

cam

elid

s

Rab

ies

(E)

rabi

a (F

) ra

ge

(D)

Tol

lwut

Lys

savi

rus

(Rha

bdov

irid

ae)

Enc

epha

litis

Y

es

Yes

Foo

t an

d m

outh

dis

ease

(E

) fi

ebre

aft

osa

FM

D v

irus

O

ral

vesi

cles

Y

es

Mild

dis

ease

(F

MD

) (F

) fi

èvre

aph

teus

e (D

) M

aul-

und

Kla

uens

euch

e (P

icor

navi

rida

e)

Ves

icul

ar s

tom

atit

is (

VS

) (E

) es

tom

atit

is v

esic

ular

(F

) st

omat

ite

vési

cule

use

(D)

vesi

kulä

re S

tom

atit

is

VS

viru

s (R

habd

ovir

us)

Ora

l ve

sicl

es

Exp

erim

enta

l Y

es

Bor

na d

isea

se

Bor

na d

isea

se v

irus

(N

ot c

lass

ifie

d)

Enc

epha

litis

Y

es

Yes

Rin

derp

est

(E)

pest

e bo

vina

(F

) pe

ste

bovi

ne

(D)

Rin

derp

est

Rin

derp

est

viru

s (P

aram

yxov

irid

ae)

Seve

re g

astr

oent

erit

is

Yes

N

R

Ret

inal

deg

ener

atio

n E

quin

e he

rpes

viru

s ty

pe 1

R

etin

al d

egen

erat

ion

and

ence

phal

itis

N

R

Yes

Con

tagi

ous

ecth

yma,

(E

) ec

tim

a co

ntag

ioso

E

cthy

ma

viru

s E

pide

rmal

pro

lifer

atio

n Y

es

Yes

so

re m

outh

, or

f (F

) ec

thym

a co

ntag

ieux

(D

) D

ecth

yma

Kon

tagi

os

(Par

apox

viru

s)

Blu

eton

gue

(E)

leng

ua a

zul

(F)

lang

ue b

leue

(D

) D

ürch

enzu

ng b

laus

ucht

Blu

eton

gue

viru

s (O

rbiv

irus

) P

anvi

raem

ia

SO

SO

(E):

Spa

nish

(F

): F

renc

h (D

): G

erm

an

NR

: no

t re

port

ed

SO:

sero

logi

cal

resp

onse

onl

y

160 T

AB

LE

III

Fun

gal

and

bact

eria

l di

seas

es

of

Cam

elid

ae

(1,

2, 4

)

Dis

ease

nam

e in

Eng

lish

Oth

er l

angu

age

equi

vale

nts

Org

anis

m

Synd

rom

e

Susc

eptib

ility

Sout

h C

amel

A

mer

ican

ca

mel

ids

Der

mat

ophy

losi

s, (E

) tin

a Tr

icho

phyt

on v

erru

cosu

m,

Alo

peci

a, d

erm

al t

hick

enin

g,

Yes

Y

es

ring

wor

m

(F)

teig

ne

T. m

enta

grop

hyte

s va

r.

prur

itis

(D)

Flec

hte

men

tagr

ophy

tes,

M

icro

spor

um s

pp.

Can

dido

sis,

mon

ilios

is

(E)

cand

idos

is

Can

dida

alb

ican

s G

astr

oint

estit

is

Yes

Y

es

(F)

Can

dido

se

(D)

Kan

dida

myk

ose

Asp

ergi

llosi

s (E

) as

perg

ilosi

s A

sper

gillu

s fu

mig

atus

Pn

eum

onia

, en

ceph

aliti

s Y

es

Yes

(F

) as

perg

illos

e (D

) A

sper

gillo

sis

Coc

cidi

oido

myc

osis

, (E

) co

ccid

ioid

omic

osis

C

occi

dioi

des

imm

itus

Pneu

mon

ia a

nd d

isse

min

ated

N

R

Yes

valle

y fe

ver

(F)

cocc

idio

idom

ycos

e gr

anul

omas

(D

) C

occi

dioi

dom

ycos

is

Tet

anus

(E

) té

tano

s C

lost

ridi

um t

etan

i G

ener

aliz

ed t

etan

y Y

es

Yes

(F

) té

tano

s (D

) T

etan

us

Ent

erot

oxae

mia

C

lost

ridi

um p

erfr

inge

ns

Var

iabl

e ef

fect

s on

cen

tral

Y

es

Yes

ty

pes

A, C

and

D

nerv

ous

and

gast

roen

teri

c sy

stem

s, s

udde

n de

ath

Bot

ulis

m

(E)

botu

lism

o C

lost

ridi

um b

otul

inum

Fl

acci

d pa

raly

sis

Yes

Y

es

(F)

botu

lism

e (D

) B

otul

ism

us

Mal

igna

nt o

edem

a C

lost

ridi

um s

eptic

um

Wou

nd c

ellu

litis

Y

es

Yes

161

Tub

ercu

losi

s (E

) tu

berc

ulos

is

Myc

obac

teri

um b

ovis

, P

ulm

onar

y an

d d

isse

min

ated

Y

es

Yes

, but

not

(F

) tu

berc

ulos

e M

. av

ium

, M.

kans

asii

gr

anul

omas

hi

ghly

(D

) T

uber

culo

se

cont

agio

us

Par

atub

ercu

losi

s,

(E)

para

tube

rcul

osis

M

ycob

acte

rium

E

nter

itis

Y

es

Yes

, bu

t no

t Jo

hne'

s di

seas

e (F

) pa

ratu

berc

ulos

e (D

) P

arat

uber

kulo

se

para

tube

rcul

oisi

s hi

ghly

co

ntag

ious

Ant

hrax

(E

) an

trax

mal

igno

(F

) fi

èvre

cha

rbon

neus

e (D

) M

ilzbr

and

Bac

illu

s an

thra

cis

Pan

sept

icae

mia

Y

es

Yes

Bru

cello

sis,

und

ulan

t (E

) br

ucel

osis

B

ruce

lla

abor

tus

Abo

rtio

n, i

nfer

tilit

y Y

es

NR

fe

ver

(F)

bruc

ello

se

(D)

Bru

zello

se

B.

mel

iten

sis

? Y

es

Lis

teri

osis

(E

) lis

tere

losi

s (F

) lis

teri

ose

(D)

Lis

teri

ose

Lis

teri

a m

onoc

ytog

enes

E

ncep

halit

is

Yes

Y

es

Col

ibac

illos

is

(E)

coli

baci

losi

s (F

) co

liba

cill

ose

(D)

Kol

ibaz

illo

se

Esc

here

chia

col

i M

etri

tis,

mas

titi

s, s

epti

caem

ia,

endo

toxa

emia

Y

es

Yes

Nec

roba

cillo

sis

(E)

necr

obac

ilosi

s (F

) ne

crob

acill

ose

(D)

Nec

roba

zillo

se

Fus

obac

teri

um n

ecro

phor

um N

ecro

tizi

ng l

esio

ns o

f th

e fa

cial

bo

nes

Yes

Y

es

Act

inom

ycos

is,

(E)

acti

nom

icos

is

Act

inom

yces

sp

. A

bsce

sses

N

R

Yes

lu

mpy

ja

w

(F)

acti

nom

ycos

e (D

) St

rahl

enpi

lz-k

rank

heit

en

Stre

ptoc

occo

sis

(E)

estr

epto

coco

sis

(F)

stre

ptoc

occo

se

(D)

Stre

ptok

okko

se

Stre

ptoc

occu

s sp

p.

Sept

icae

mia

, ab

sces

ses

Yes

Y

es

Noc

ardi

osis

(E

) no

card

iasi

s (F

) no

card

iose

(D

) N

ocar

dios

e

Noc

ardi

a as

tero

ides

A

bsce

sses

, se

ptic

aem

ia

NR

Y

es

NR

: n

ot r

epor

ted

(E):

Spa

nish

(F

): F

renc

h (D

): G

erm

an

162

Tuberculosis is not a major disease of camelids, but these species do occasionally develop the disease. Both natural and experimental infections have been reported for the four major species of acid-fast staining mycobacteria (Mycobacterium bovis, M. tuberculosis, M. avium and M. paratuberculosis) (3). Most infections have occurred when camelids have lived in close association with other infected livestock or infected humans. The use of intradermal tuberculin as a means of evaluating an individual camelid or a herd for the presence of tuberculosis has proved less than satisfactory. Both false-positive and false-negative reactions have been described. A recent study, conducted on llamas in Argentina, correlated intradermal testing with a panel of serological tests. Preliminary reports on the study indicate that more satisfactory testing procedures may be available.

Actinomyces (lamae) causes a bacterial infection unique to South American camelids. The disease usually manifests as a thick-walled abscess in the throat region, lungs or liver, but the organism has also been recovered from apical dental abscesses. This organism may be under-reported, as it is a Gram-positive, short rod which may be mistaken for a coccus. Abscesses caused by streptococci, micrococci and corynebacterium heal permanently if surgically incised, drained and irrigated, whereas actinomyces abscesses temporarily heal only to reappear, unless long-term (4-6 weeks) antibiotic therapy is administered.

Parasitism (11, 15)

The major parasitic diseases of camelids are listed in Table IV. A brief discussion of a few important parasitic diseases of camelids is presented below.

Three types of mange have been reported from camelids: sarcoptic, psoroptic and chorioptic (8). Of these, sarcoptic mange is the most common and troublesome. The true identity of the mite must be established to institute effective therapy and to determine whether or not the case must be reported to regulatory authorities. Psoroptic mange (scab) is a reportable disease in the United States of America, and all forms of mange are reportable in certain states. Sarcoptic mange and trypanosomosis are the most important parasitic diseases of camels.

The sarcoptic mite burrows into the epidermis causing hyperaemia, papules and pustules, which become encrusted. The skin becomes thickened in affected areas and loses its vitality, becoming susceptible to secondary bacterial infection, with subsequent exudation. Pruritus is common. Lesions are usually found on the limbs, between the toes and on the medial thighs, ventral abdomen, chest and axilla, on the perineum of the female and on the prepuce of the male.

The parasites which are important in camelid herds or flocks in South America have been studied intensively. Those of lesser importance are rarely investigated. The lack of reported instances of parasitism from major taxonomic groups may simply reflect a failure to observe, identify or report. To date, only seventy-five species of parasites have been reported as causing clinical disease in South American camelids. South American camelids share no nematode genera with equids.

Two parasitic diseases of South American camelids warrant additional comment, as the llama or alpaca serves as an aberrant host and the parasitism may be lethal. The deer nasopharyngeal bot, or deer nasal bot (Cephenemyia spp.) is ubiquitous wherever cervids are found (10). The adult fly is approximately 14 mm in length. First instar

163

larvae are approximately 1 mm long, and progress to third instar larvae which vary from 12-40 mm. A third instar larva removed from the nasopharynx of a llama was cream-coloured, 2.5 cm long and approximately 0.7 cm in diameter (10). In the llama or alpaca, the irritation of only a single larva may stimulate production of a granuloma which obstructs the nasal airway. Llamas and alpacas are obligate nasal breathers, and this malady can therefore be lethal if not diagnosed and treated appropriately.

The meningeal worm (Parelaphostrongylus tenuis) of the white-tailed deer (Odocoileus virginianus) is well adapted to the primary host, in which little or no clinical disease develops. In aberrant hosts, such as the llama or alpaca, migration of the larvae through the spinal cord produces neurological defects commensurate with the location of the larvae, including lameness, ataxia, stiffness, circling, blindness, hypermetria, paralysis and death (8).

The following gastrointestinal nematodes are found in racing camels in the United Arab Emirates (listed in order of prevalence) (12):

- Haemonchus - Trichostrongylus - Nematodirus - Oesophagostumum - Strongyloides - Camelostrongylus - Marshallagia - Trichuris - Bunostomum - Ostertagia.

Similar findings have been reported from Iraq, Tunisia, Ethiopia, Saudi Arabia, Egypt, Sudan and India (12).

Old World camels are highly susceptible to infection with a number of species of Trypanosoma. Camels are seldom used in Africa in the region called the 'tsetse fly belt'. Illness and death due to nagana - the disease caused by T. brucei - may be the key factor in the absence of these animals from the area. T. evansi is the major trypanosome affecting camels, causing a disease called surra. 'Surra' in the Marathu language (India) means 'rotten'. T. evansi may have some significance in South American camelids (see below). Any biting or blood-sucking insect or tick may serve as a vector. Mechanical transmission via contaminated hypodermic needles is also possible.

The geographical distribution of T. evansi is extensive. This parasite causes disease in North Africa, Asia Minor, the former Soviet Union, Pakistan, Afghanistan, India, Burma, Malaya, Indochina, southern China, Indonesia and the Philippines. Trypanosomosis has not been reported in South American camelids in Central and South America, despite the presence of the organism. Acute surra is characterized by fever, depression, weakness and oedema. The presence of pulmonary oedema may contribute to the development of secondary pneumonia. Females may abort, and the milk of lactating females may become caseous. Large numbers of trypanosomes may be seen in peripheral blood samples. Death may occur within a few weeks of infection.

164

TA

BL

E IV

Sele

cted

par

asiti

c di

seas

es

of

cam

elid

ae

(5,

7, 1

6)

Susc

eptib

ility

Dis

ease

/com

mon

nam

e O

rgan

ism

L

ife c

ycle

Sy

ndro

me

Cam

el

Sout

h A

mer

ican

ca

mel

ids

Pedi

culo

sis,

lic

e D

amal

inia

bre

vice

ps

Mic

roth

orac

is c

amel

i C

ompl

eted

on

the

host

A

lope

cia

and

prur

itis

Yes

Y

es

Man

ge

Sarc

opte

s sc

abei

P

soro

ptes

spp

. C

hori

opte

s sp

p.

Com

plet

ed o

n th

e ho

st

Thi

cken

ed,

crus

ty s

kin

Yes

Y

es

Try

pano

som

osis

Tr

ypan

osom

a ev

ansi

(sur

ra)

Tryp

anos

oma

spp.

Sp

read

by

bitin

g in

sect

s A

naem

ia

Yes

Y

es

Coc

cidi

osis

E

imer

ia s

pp.

(uni

que

to c

amel

ids)

D

irec

t E

nter

itis,

diar

rhoe

a Y

es

Yes

Tox

opla

smos

is

Toxo

plas

ma

gond

ii Fe

ed

cont

amin

ated

with

cat

faec

es

Var

iabl

e de

pend

ing

on t

he

orga

n af

fect

ed

Yes

Y

es

Liv

er f

luke

s F

asci

ola

hepa

tica

Fas

ciol

oide

s m

agna

In

term

edia

te h

osts

are

aqu

atic

sn

ails

H

epat

ic i

nsuf

ficie

ncy

Yes

Y

es

Hyd

atid

dis

ease

E

chin

ococ

cus

gran

ulos

a Pr

imar

y ho

st i

s a

carn

ivor

e V

aria

ble

depe

ndin

g on

the

or

gan

affe

cted

Y

es

Yes

Tap

ewor

ms

Man

y sp

ecie

s (e

.g. M

onie

zia

expa

nsa)

In

term

edia

te h

osts

are

or

abat

id m

ites

Wei

ght

loss

and

dia

rrho

ea

Yes

Y

es

165

Stom

ach

wor

ms

Tric

host

rong

ylus

spp

. O

ster

tagi

a sp

p.

Cam

elos

tron

gylu

s sp

p.

Hae

moc

hus

spp.

G

raph

inem

a sp

p.

Spic

ulop

tera

gia

spp.

Dir

ect

Gas

triti

s Y

es

Yes

Whi

pwor

ms

Tric

huri

s sp

p.

Dir

ect

Ente

ritis

, di

arrh

oea

Yes

Y

es

Inte

stin

al n

emat

odes

N

emat

odir

us s

pp.

Oes

opha

gost

umum

spp

. N

umer

ous

othe

r sp

ecie

s

Dir

ect

Ente

ritis

Y

es

Yes

Lung

wor

ms

Dic

tyoc

aulu

s sp

p.

Dir

ect

Bron

chiti

s, pn

eum

onia

Y

es

Yes

Men

inge

al w

orm

P

arel

apho

stro

ngyl

us t

enui

s In

term

edia

te h

osts

ar

e te

rres

tria

l sn

ails

and

slug

s A

taxi

a, p

arap

legi

a, p

aral

ysis

NR

Y

es

Abe

rran

t ho

st

•Hoo

kwor

ms

Bun

osto

mum

spp

. D

irec

t A

naem

ia,

diar

rhoe

a Y

es

Yes

Lam

anem

a ch

avez

ii D

irec

t La

rvae

mig

rate

to

the

liver

and

lu

ng

Hep

atop

athy

, en

teri

tis,

repo

rted

onl

y in

So

uth

Am

eric

a

NR

Y

es

NR

: no

t re

port

ed

166

Chronic surra is characterized by intermittent episodes of fever, anaemia, pendant oedema and emaciation. Between episodes of fever, the parasite may be absent from peripheral blood vessels. A camel may live for three or four years, depending on the care provided.

Coccidia spp. tend to be host-specific and, in the case of camelids, a few species of the genus Eimeria have been described. To the knowledge of the author, camelids do not host any species of Coccidia except those for which they are unique hosts.

Nematode species are the most numerous and detrimental of the camelid parasites. Most of these parasites are located in the gastrointestinal tract. Species identification of the gastrointestinal parasites of South American camelids in North America has never been reported. Thus it is not known whether these parasite species are the same as those found in cattle, sheep and goats, or different species from the same genera. In general, it is assumed that camelids and ruminants share the same gastrointestinal nematodes. Although taxonomic information is important from an epidemiological standpoint, this will not be available until a classical taxonomist of parasites takes an interest in camelids. Many aspects of gastrointestinal parasitism are similar, regardless of which species of parasite is involved. Most gastrointestinal parasites produce a protein-losing gastroenteropathy. In severe cases, hypoalbuminaemia may develop. Enteritis will induce changes in the secretory status of the gut. Appetite and utilization of the feed consumed is reduced, depriving the body of vital nutrients. Absorption of calcium and phosphorus is depressed, causing arrested skeletal development in the young animal. Selenium uptake is also retarded. Young animals are at greatest risk when affected by parasitism, as no resistance has been developed to the invading organisms. There are peracute, acute and chronic forms of most parasitisms. Death may be caused by overwhelming invasion of an organ or system, but parasitism usually results only in varying degrees of debilitation. Over a period of time, the body loses the ability to resist minor infectious agents, and a secondary infection may cause death. Some degree of ill thrift usually accompanies parasitism. The fibre coat may lack lustre.

Diarrhoea is the most prominent sign of enteritis but need not always be present in parasitism, especially when larvae invade such tissues as the liver or lungs. Anaemia may be observed during heavy infestations, even with parasites which are not blood-suckers. The cutting mouthparts which the parasite uses for attachment may result in leakage of plasma and cells from capillaries. In adult animals, production and quality of fibre and milk will be depressed. Thus a juvenile may be doubly jeopardized, both by its own parasite load and by lack of nourishment as a result of the effect of parasitism on the mother.

Lamanema chavezi is one of the more important nematode parasites of camelids in South America. Fortunately, no instances of parasitism outside South America have been reported.

Ingested larvae penetrate the intestinal wall and migrate to the liver and lungs. The most serious damage occurs in the liver. Ultimately, maturation of the larvae is completed, with migration back to the small intestine via the trachea.

Whipworms (Trichuris spp.) are significant parasites of camelids, and are resistant to treatment with the usual doses of anthelmintics which are effective for other gastrointestinal nematodes. These parasites are characterized by long, slender anterior segments and a thicker posterior segment. Adult parasites are found in the caecum and

167

large intestine. Trichurids identified from camels include T. globulosa, T. cameli and T. skrjabini. Whipworms cause a marked enteritis, leading to diarrhoea, dehydration and weight loss.

Zoonoses

Infectious zoonoses include rabies, encephalomyocarditis, contagious ecthyma, Rift Valley fever, numerous viruses spread by ticks, in addition to anthrax, plague, salmonellosis, leptospirosis, colibacillosis, dermatophilosis, brucellosis and tuberculosis. Camelids are not major carrier hosts for any of these diseases. Parasitic zoonoses include trypanosomosis and sarcoptic mange.

Diseases of camelids acquired from other species

Gastrointestinal nematodes may be shared between ruminants and camelids. South American camelids have become infected with EHV-1 and two parasite species, namely Cephenemyia spp. and Parelaphostrongylus tenuis. Camelids may also acquire numerous bacterial diseases from other species.

*

ÉLEVAGE ET PATHOLOGIE DES CAMÉLIDÉS. - M.E. Fowler.

Résumé : Depuis des millénaires, les hommes de l'Ancien et du Nouveau Monde utilisent les camélidés pour leur viande, leur lait, leur laine et leur graisse, et en tant que bêtes de somme pouvant porter de lourds fardeaux. Depuis l'apparition des véhicules motorisés, l'utilisation des camélidés est devenue obsolète, sauf dans certaines situations exceptionnelles. Le nombre de ces animaux a donc considérablement diminué. Cette situation s'inverse actuellement, car l'on a finalement admis que les camélidés ont une meilleure utilité dans leur environnement naturel que n'importe quel autre animal domestique. Les camélidés ont toujours été très appréciés dans les parcs zoologiques. Les chameaux, ainsi que deux espèces camélines d'Amérique du Sud, sont des animaux qui supportent très bien la captivité. Ils montrent une capacité exceptionnelle à se nourrir de fourrages épineux. Les caractéristiques de ces espèces en termes de reproduction les distinguent également des autres animaux de rente.

Peu de maladies des camélidés leur sont spécifiques ; les camélidés ne constituent un réservoir pour aucune maladie grave du bétail.

MOTS-CLÉS : Alpagas — Chameaux - Dromadaires — Faune sauvage — Guanacos - Infection - Lamas - Parasitisme - Vigognes.

*

CRÍA Y PATOLOGÍA DE LOS CAMÉLIDOS. - M.E. Fowler.

Resumen: Los camellos del Viejo y del Nuevo Mundo constituyeron durante milenios fuente de carne, leche, fibra y combustible para las poblaciones humanas indígenas, además de servir como bestias de carga para el transporte.

168

Con la llegada de los vehículos de motor, el empleo de camellos se volvió obsoleto, salvo en ciertas situaciones muy particulares. El número de camellos menguó de forma espectacular. Hoy esta tendencia se está invirtiendo, pues se ha constatado que estos animales son mucho más eficaces, en su entorno natural, que cualquier otra especie de animales de renta. Los camélidos siempre han sido populares en los zoológicos. Los camellos, junto con otras dos especies de camélidos sudamericanos, son animales domésticos que se adaptan con facilidad al manejo en espacios limitados. Poseen una capacidad única para alimentarse con forrajes extremadamente ásperos. Su fisiología reproductiva es distinta de la de cualquier otra especie doméstica.

Pocas de las enfermedades de los camélidos son exclusivas de estas especies. Los camélidos no son reservonos para ninguna de las enfermedades importantes del ganado.

PALABRAS CLAVE: Alpacas - Camellos - Dromedarios - Fauna salvaje - Guanacos - Infección - Llamas - Parasitismo — Vicuñas.

* * *

REFERENCES

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2. APPLEBY E.C. & HEAD D.K. (1954). - A case of suspected Johne's disease in a llama (L. glama). J. comp. Pathol., 4, 52-53.

3. CASTAGNINO ROSSI D., SINGER I.N. & HERNANDEZ DONGO J. (1986). - Tuberculosis

experimental en alpacas, Lama pacos: nota preliminar [Experimental tuberculosis in alpacas: preliminary notes]. Bol. extraordinario, 3, 75-77.

4. FIENNES R.N.T.-W. (1965). - An outbreak of brucellosis in camels, llamas, and ibex in the London Zoo. Verhandl.ber. Erkg. Zootiere, 7, 153-158.

5. FOWLER M.E. (1985). - Tick paralysis. Calif. Vet., 39 (2), 25-26.

6. FOWLER M.E. (1986). - Camelids. In Zoo and wild animal medicine (M.E. Fowler, ed.), 2nd Ed. W.B. Saunders, Philadelphia, Pennsylvania, 969-981.

7. FOWLER M.E. (1986). - Lice in llamas. Avian exotic Practice, 3 (1), 22-25.

8. FOWLER M.E. (1989). - Medicine and surgery of South American camelids. Iowa State University Press, Ames, Iowa, 391 pp.

9. FOWLER M.E. (1995). - Restraint and handling of wild and domestic animals, 2nd Ed. Iowa State University Press, Ames, Iowa, 383 pp.

10. FOWLER M.E. & PAUL-MURPHY J. (1985). - Cephenemyia sp. infestation in the llama. Calif. Vet., 39, 10-12.

11. GEORGI J.R. (1985). - Parasitology for veterinarians, 4th Ed. W.B. Saunders, Philadelphia, Pennsylvania, 344 pp.

12. KAYUM A., AFZAL M. & SALMAN R. (1992). - Gastrointestinal parasites in racing camels: prevalence and evaluation of different methods of fecal examination. In Proc. First International Camel Conference (W.R. Allen, A.J. Higgins, I.G. Mayhew,

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D.H. Snow & F.J. Wade, eds). Dubai, United Arab Emirates, 2-6 February. R and W Publications, Newmarket, United Kingdom, 85-87.

13. MUNOZ E. (1992). - Pox and pox-like diseases in camels. In Proc. First International Camel Conference (W.R. Allen, A.J. Higgins, I .G. Mayhew, D.H. Snow & F.J. Wade, eds). Dubai, United Arab Emirates, 2-6 February. R and W Publications, Newmarket, United Kingdom, 43-46.

14. REBHUN W.C., JENKINS D.H., Rus R.C., DILL S.G., DUBOVI E.J. & TORRES A. (1988). - An epizootic of blindness and encephalitis associated with a herpesvirus indistinguishable from equine herpesvirus 1 in a herd of alpacas and llamas. J. Am. vet. med. Assoc., 192 (7), 953-954.

15. SOULSBY E.J.L. (1982). - Helminths, arthropods and protozoans of domesticated animals, 7th Ed. Lea and Febiger, Philadelphia, Pennsylvania, 809 pp.

16. VANZOLINI P.E. & GUIMARES L.R. (1955). - South American land mammals and their lice (llama). Evolution, 9, 345-347.

17. WERNERY U. & KAADEN O.-R. (1995). - Infectious diseases of camelids. Blackwell Wissenschafts-Verlag, Berlin, 133 pp.

18. WHEELER J. (1995). - Evolution and present situation of the South American Camelidae. Biol. J. Linnean Soc., 54, 271-295.