ArticlePDF Available

PREVALENCE OF GIT HELMINTHS IN CATTLE AT THE VICINITIES OF TEHSIL JATOI, PUNJAB, PAKISTAN

Authors:
Sci.Int.(Lahore),25(2),305-309,2013 ISSN 1013-5316; CODEN: SINTE
305
PREVALENCE OF GIT HELMINTHS IN CATTLE AT THE
VICINITIES OF TEHSIL JATOI, PUNJAB, PAKISTAN
Muhammad Asif Raza*, Muhammad Mazhar Ayaz1, Saeed Murtaza1, Muhammad Saleem Akhtar1,
Muhammad Naeem2, Muhammad Ali1 and Hafiz Allah Bachaya3
*Animal Husbandry in Tropics and Subtropics, University of Kassel, Germany/
University of Agriculture, 38040, Faisalabad, Pakistan
1Faculty of Veterinary Sciences, Bahauddin Zakariya University, Multan, Pakistan
2Institute of Pure and Applied Biology, Zoology Division, Bahauddin Zakariya University, Multan, Pakistan
3Livestock & Dairy Development Department, Punjab, Pakistan
*Corresponding author: asifrazarana@yahoo.com, asif-raza@icdd.uni-kassel.de
ABSTRACT: Main purpose of this study was the investigation of helminth’s prevalence in cattle.
Therefore, 500 faecal samples of cattle, were examined by direct, indirect (sedimentation and floatation
techniques) and coproculture techniques.Species recorded were Fasciola hepatica, Fasciola
gigentica, Toxocara vitulorum, Paramphistomum cervi, Monezia expansa, Monezia bendeni,
Oesophagostomum radiatum, Haemonchus placei and Bunostomum phlebotomumn in cattle, an overall
prevalence of helminths was 51% (255/500). The highest prevalence (105/500; 21%) was recorded for
nematodes followed by trematodes (85/500; 17%), cestodes (10/500; 2%) and mixed helminth infections
(55/500; 11%). A total of nine species of helminths including four nematodes, i.e. Toxocara vitulorum,
Oesophagostomum radiatum, Bunostomum phlebotomum, Haemonchus placei; three trematodes, i.e.
Fasciola hepatica, F. gigantica, Paramphistomum cervi; and two cestodes, i.e. Moniezia expansa, M.
benedeni, were recorded. Toxocara vitulorum was the most prevalent species of helminth followed by
Fasciola hepatica, Paramphistomum cervi, Oesophagostomum radiatum, Bunostomum phlebotomum,
Haemonchus placei, Moniezia expansa, M. benedeni and F. gigantica. The mixed helminth infection
(55/500; 11%) was often composed of 10 species including Fasciola hepatica, F. gigantica, Toxocara
vitulorum, Moniezia expansa, Trichostrongylus spp., Paramphistomum cervi, Haemonchus placei,
Oesophagostomum radiatum, Bunostomum phlebotomum and Cooperia spp. To know the dependence of
helminth’s prevalence on sex and age of animal Chi-square statistical design was applied to data. All the
results were non significant due to some factors which directly affects the helminth’s prevalence.
Key words: Cattle, Helminthes, Prevalence, Jatoi, Pakistan
INTRODUCTION
The gastrointestinal tracts (GIT) of animals harbor a variety
helminthes, which causes clinical and sub clinical
parasitism. Helminthes adversely affect the health status of
animals which may be a cause of economic losses to the
livestock industry. Helminthes has been noted as major
constraint to ruminants’ productivity on a clinical and
subclinical level [1]. Helminthes are recognized as by for the
most significant part of diseases in livestock sector [2;3].
Milk production is considerably declined due to helminthes
infestation in cattle and buffalo [4]. The most important
predisposing factors of helminthes infection are grazing
habits, climates, nutritional deficiency, pasture management,
immunological status presence of intermediate host and
vector and the number of infective larvae and eggs in the
environment [5]. Due to infestation of helminthes fallowing
damages inflicted to the health and productivity includes
loss in body weight, poor reproductive performance,
digestive disturbance, and emaciation for longer period [5].
Toxins are produced by mature worms that destroy Red
Blood Cells, due to which unthrifty anemic conditions are
generated. While immature worms migrating through the
body tissues of animals open the way for bacteria and fungi
to enter, which cause serious diseases. Other economic
losses are involuntary culling, poor work performance,
treatment costs, lower milk production and mortality in
heavily parasitized animals [6]. So it is important to control
internal parasites especially helminthes with better
management as in developed countries, and knowledge on
prevalence of these parasites is mandatory. In Pakistan,
parasitism is one of the major menaces for livestock, causing
obstacles in the development of profitable livestock industry,
like in cattle and buffaloes [7]. Keeping in view these
considerations, this study was designed to investigate the
prevalence of helminthes in cattle of Tehsil Jatoi (District
Muzaffar Garh).
MATERIALS AND METHODS
The present study was conducted to determine the
prevalence of gastrointestinal helminthes, under field
conditions, in cattle at the localities of Tehsil Jatoi of District
Muzaffar Garh, Punjab, Pakistan.
Sample Collection
Five hundred faecal samples of cattle were randomly
collected in sterile polythene bags directly from rectum of
each animal. These faecal samples were brought to District
Diagnostic Lab. Muzaffar Garh for identification of
eggs/larvae of helminthes or the adult parasites.
Faecal Examination
Faecal samples taken from 500 cattle were examined for
helminthes eggs/larvae by using direct and indirect
techniques and for identification of certain nematodes,
ISSN 1013-5316; CODEN: SINTE Sci.Int.(Lahore),25(2),305-309,2013
306
coproculture were performed to obtain larval stage. Both
eggs and larvae from coproculture were identified by using
standard techniques as described by MAFF [8] and Soulsby
[9]. Briefly, one gram of faecal sample was mixed well in a
drop of water and a relatively homogenous and transparent
preparation was obtained and examined under microscope
by placing a drop of suspension on slide with cover slip. At
least three direct smears were examined from each sample.
All the samples were also examined by concentration
techniques, i.e. floatation and sedimentation.
For floatation technique, five grams of faeces was mixed in
30-50 mL of water and strained through a sieve to remove
the course material. The mixture was allowed to sediment
for half an hour. The supernatant was poured off and
sediment was mixed in a saturated solution of common salt.
The suspension was centrifuged at 1000 rpm for two
minutes. The upper 0.1 mL of centrifuged suspension was
transferred to a glass slide and examined under microscope
at 10 X for the presence of helminthes eggs.
For sedimentation technique, five grams of faeces was
mixed in 30-50 mL of water and strained through a sieve to
remove the course material. The mixture was allowed to
sediment for half an hour. After centrifugation, the
supernatant was decanted and washing was continued until
supernatant became clear. A drop was taken from sediment
with Pasteur’s pipette on slide and was examined under
microscope at 10 X for the presence of helminthes eggs.
Copro-culture
Faecal cultures provide an environment suitable for hatching
of helminth eggs and for their development. Faeces found
positive for nematode eggs but confusing for exact
identification were broken up finely, using either a large
pestle and mortar or spatula and were placed in a glass jar or
petridishes which was closed and incubated at a temperature
of about 26 ˚C for 7 days. After incubation, samples were
examined for larvae. Larvae were identified with the help of
keys given by MAFF [8].
Statistical Analyses
Data on the prevalence of helminthiasis was analyzed using
Chi-square satatistical design on the basis of sex and age.
Graphical representation of data was also done.
RESULTS
The present study was undertaken from January to June
2009 to determine the prevalence of gastrointestinal
helminths in cattle, in Tehsil Jatoi District Muzaffar Garh.
In cattle, an overall prevalence of helminths was 51%
(255/500). The highest prevalence (105/500; 21%) was
recorded for nematodes followed by trematodes (85/500;
17%), cestodes (10/500; 2%) and mixed helminth infections
(55/500; 11%). A total of nine species of helminths
including four nematodes, i.e. Toxocara vitulorum,
Oesophagostomum radiatum, Bunostomum phlebotomum,
Haemonchus placei; three trematodes, i.e. Fasciola
hepatica, F. gigantica, Paramphistomum cervi; and two
cestodes, i.e. Moniezia expansa, M. benedeni, were
recorded. The prevalence of different species of helminthes
is presented in Table I. Toxocara vitulorum was the most
prevalent species of helminth followed by Fasciola
hepatica, Paramphistomum cervi, Oesophagostomum
radiatum, Bunostomum phlebotomum, Haemonchus placei,
Moniezia expansa, M. benedeni and F. gigantica. The mixed
helminth infection (55/100; 11%) was often composed of 10
species including Fasciola hepatica, F. gigantica, Toxocara
vitulorum, Moniezia expansa, Trichostrongylus spp.,
Paramphistomum cervi, Haemonchus placei,
Oesophagostomum radiatum, Bunostomum phlebotomum
and Cooperia spp.
The results of age-wise prevalence in cattle revealed 34%
adults (105/305) and 77% calves (150/195) having infection
with one or the other species of helminthes. The prevalence
of helminthes was higher in young animals as compared to
old cattle.
In cattle (Table VI), calves were found infected with seven
species of helminthes, i.e. Toxocara vitulorum, Fasciola
hepatica, Paramphistomum cervi, Oesophagostomum
radiatum, Bunostomum phlebotomum, Haemonchus placei
and Moniezia expansa; whereas, from adults, six species of
helminthes were recorded, i.e. T. vitulorum, F. hepatica, P.
cervi, O. radiatum, B. phlebotomum and F. gigantica in the
order of deceasing prevalence. A total of 11% cattle
(55/500) had mixed infection comprising 18% (35/195) in
calves and 7% (20/305) in adults. The mixed infections were
either with two, three or four species of helminthes.
The results on sex-wise prevalence in cattle revealed 65%
males (100/155) and 45% females (155/345) having
infection with one or the other species of helminthes. In
buffaloes, 91% males (100/110) and 35% females (110/390)
were infected with the helminthes. As far as small ruminants
were concerned, in sheep, 77% male (150/195) and 52%
females (160/305); and in goats, 56% male (120/215) and
49% females (140/285) were found infected.
In cattle (Table X), five species of helminthes i.e. T.
vitulorum, F. hepatica, P. cervi, O. radiatum and M.
expansa were recorded from males and eight species i.e. T.
vitulorum, F. hepatica, P. cervi, O. radiatum, B.
phlebotomum, H. placei, M. benedeni and F. gigantica from
females were recorded in the order of decreasing prevalence.
Table X. Sex-wise prevalence of different species of
helminths in cattle in Tehsil Jatoi, District Muzaffar Garh.
DISCUSSION
Helminthiasis is one of the major problems which affect the
productivity of cattle. Losses caused by helminthes
invariably depend on the prevalence, nature and intensity of
infection and the management practices. In this
investigation, highest prevalence of helminthes was recorded
in cattle. The prevalence of helminthes was higher in young
animals compared with the older ones, and higher in males
compared with the females in the study. A total of nine
species of helminthes (four nematodes i.e. Toxocara
vitulorum, Oesophagostomum radiatum, Bunostomum
phlebotomum, Haemonchus placei; three trematodes i.e.
Sci.Int.(Lahore),25(2),305-309,2013 ISSN 1013-5316; CODEN: SINTE
307
Table I. Prevalence of different species of helminths in cattle.
Species of helminth Number of Faceal Samples
Examined Number of Faecal Samples
Positive Per cent Infected
Toxocara vitulorum 500 75 15%
Fasciola hepatica 500 45 9%
Paramphistomum cervi 500 35 7%
Oesophagostomum radiatum 500 15 3%
Bunostomum phlebotomum 500 10 2%
Haemonchus placei 500 5 1%
Moniezia expansa 500 5 1%
M. benedeni 500 5 1%
F. gigantica 500 5 1%
Table II. Age-wise prevalence of different species of helminths in cattle in Tehsil Jatoi, District Muzaffar Garh
Species of helminth Calf Adult
Toxocara vitulorum 50/195; 25.64% 25/305; 8.19%
Fasciola hepatica 25/195; 12.82% 20/305; 6.55%
Paramphistomum cervi 20/195; 10.25% 15/305; 4.91%
Oesophagostomum radiatum 5/195; 2.56% 10/305; 3.27%
Bunostomum phlebotomum 5/195; 2.56% 5/305; 1.63%
Haemonchus placei 5/195; 2.56% 0/305; 0%
Moniezia expansa 5/195; 2.56% 0/305; 0%
M. benedeni 0/195; 0% 5/305; 1.63%
F. gigantica 0/195; 0% 5/305; 1.63%
Mixed infection 35/195; 18% 20/305; 7%
Overall prevalence 150/195; 77% 105/305; 34%
Table III. Sex-wise prevalence of different species of helminths in cattle in Tehsil Jatoi, District Muzaffar Garh
Species of helminth Male Female
Toxocara vitulorum 30/155; 19.35% 4/345; 13.04%
Fasciola hepatica 20/155; 12.90% 25/345; 7.24%
Paramphistomum cervi 15/155; 9.67% 20/345; 5.79%
Oesophagostomum radiatum 5/155; 3.22% 10/345; 2.89%
Bunostomum phlebotomum 0/155; 0% 10/345; 2.89%
Haemonchus placei 0/155; 0% 5/345; 1.44%
Moniezia expansa 5/155; 3.22% 0/345; 0%
M. benedeni 0/155; 0% 5/345; 1.44%
F. gigantica 0/155; 0% 5/345; 1.44%
Mixed infection 25/155; 16% 30/345; 9%
Overall prevalence 100/155; 65% 155/345; 45%
Fasciola hepatica, F. gigantica, Paramphistomum cervi; and
two cestodes, i.e. Moniezia expansa, M. benedeni) were
recorded from cattle. The helminths recorded in the study
area have also been reported previously [10;11;12;13] from
different areas of Pakistan and different parts of the world
[14;15;16;17;18;19;20;21;22]. However, these workers have
also reported some other helminthes in addition to those
recorded in the current study. Such a regional variation in
the record of various species has been widely reported. This
variation may be attributed to different geographical
distribution, host factors and climatic conditions required for
the development of free-living stages of different nematodes.
A variety of factors like age, sex and breed of the host,
grazing habits, level of education and economic capacity of
the farmers, standard of management and anthelmintic used
[23;24;25;26;27;28;29]can influence the prevalence of
helminths. During this study, most of the farmers
complained of ineffectiveness of the anthelmintics, which
may be due to development of resistance against commonly
used chemicals or their quality.
The most prevalent nematode recovered in this study from
cattle was T. vitulorum, T. vitulorum was also reported to be
the most frequently occurring nematode in cattle
[30;31;32;33;34;35]. The higher prevalence could be due to
ISSN 1013-5316; CODEN: SINTE Sci.Int.(Lahore),25(2),305-309,2013
308
the fact that this nematode has a relatively short generation
interval and ability to take the advantage of favorable
environmental conditions [36].
The climatic conditions of the study area vary from tropical
to sub-tropical, which are conducive for the development of
larval forms or intermediate hosts of helminthes. A warm
and moist summer is well suited to the development and
survival of the free-living stages of nematodes [36].
Moreover, the availability of green pastures in irrigated or
water logged area also help in perpetuation of the life cycles
of different species of helminthes. The pasture larval counts
and fecundity of different species of parasites of helminthes
also play a role in the epidemiology of helminthes.
The higher infection in young animals than that in older ones
may be attributed to lesser resistance because of lesser
exposure to different species of helminthes compared with
the older animals. It was, however, interesting to note that
prevalence was higher in males compared with females.
Normally, females are assumed to be more infected due to
stress of pregnancy and parturition. This may be due to the
practice of stall feeding females around pregnancy and thus
lesser exposure to pasture contamination. Most of the
researchers have observed higher rates of nematode
infection/worm burden in female hosts compared with the
males [23;24;37;26;28;29]. Higher prevalence of nematode
parasites in females compared with males may be because of
lowered resistance of female animals due to their
reproductive events and insufficient/unbalanced diet against
higher needs. In addition to this, host factors were
responsible for immunological impairment around
parturition and thus resulted in peri-parturient eggs rise [38].
ACKNOWLEDGMENTS
The authors are thankful to Dr. Rab Nawaz Kusar (DDLO),
Dr. Ihsan-ur-Rehman Akbar (ADIO), Dr. Hassan Farooq
Kazmi, Dr. Rana Sultan, Dr. Khalid Rasool, Dr. Nadeem
Sial and Dr. Abdul Samad Bhatti (Veterinary Officers) for
their technical support during research.
REFERENCES
[1]Martinez- Gonzalez, B., Diez-Banos, N. and Rojo-
Vazquez, F. A. An epidemiological study of gastro
intestinal parasitism in dairy sheep flocks in Leon
(NW) Spain. Small Ruminant Reseacrh, 27: 25-30,
1998.
[2] Waller, P.J. Anthelmintic, resistance, Vet. Parasitol. 72:
391-405, 1997.
[3] Waller, P.J. International approaches to the concept of
integrated control of nematodes parasites of livestock,
Int. J. Parasitol. 29: 155-164, 1999.
[4] Hayat. C.S. B. Hayat. M. Ashfaque and K. Muhammad.
Bottle jaw in Berberi (Teddy) goat. Pak. Vet. J., 4: 183,
1984.
[5] Radostits O.M., Blood D.C. and Gay C.C. 1994.
Diseases caused by helminth parasites. In: Veterinary
Medicine: a textbook of diseases of cattle, sheep, pigs,
goats and horses, 8th Edition. London, Balliere Tindall.
pp. 1223-1230.
[6] Lebbie SHB, Rey B, Irungu EK. 1994. Small ruminant
research and development in Africa. Proceeding of
the second Biennial conference of the African Small
Ruminant Research Network. ILCA. pp. 1-5.
[7] Hayat, C. S., A. A. Malik, A. H. Anwar and Z. Iqbal. An
effect of experimentally induced coccidiosis on some
blood parameters and productivity of lambs. Pak. Vet.
J., 10: 60-62, 1990.
[8] MAFF, 1979. Parasitological laboratory techniques,
Technical Bulletin No. 18. Ministry of Agriculture
Fisheries and Food Manual of Veterinary, Her
Majestey’s Stationary Office, London.
[9] Soulsby, E. J. L., Helminths, Arthropods and Protozoa of
domestic animals. 7th Ed. Baillier Tindall and Cassel
Ltd. London. 1982.
[10] Siddiqi, M. N. and M. Ashraf. Helminthiasis in goat
slaughtered in the abattoirs of Peshwar.NWFP.
Pakistan J. Agri .Res., 1: 64-75, 1980.
[11] Shah, M., S.A. Hussain and I.D. Siddiqui. Incidence of
gastrointestinal nematode parasites of sheep
slaguhtered in Municipal corporation abattoir, Lahore.
J. Anim. Hlth. Prod.,72-75, 1980.
[12] Mohiuddin, A., M. M. Khan. F. A. Mugha and M. A.
Sheikh. Taxonomy, incidence and seasonal variation of
helminth parasite of sheep and goat of Sind.
Pakistan J. Zool., 16: 25-30, 1984.
[13] Khan, M. N., C. S. Hyat, A. H. Chaudhry, A. Iqbal and
B. Hayat. Prevalence of gastrointestinal helminth in
sheep & goat at Faisalabad abattoir. Pak. Vet. J., 9:
159-161, 1989.
[14] Specht, E.J.K. Seasonal incidence of helminths in sheep
and goats in South Mozambique. Vet. Parasitol., 11:
317-328, 1982.
[15] Vercruysse, J. A survey of seasonal changes in
nematodes faecal egg count levels of sheep and goats
in Senegal. Vet. Parasitol., 13: 239-244, 1983.
[16] Hunter, A.G. and P.J. Heath. Ovine internal parasitism
in the Yemen Arab Republic. Trop. Anim. Hlth. Prod.,
16: 95-106, 1984.
[17] Gupta, R. P., C. L. Yadav and S. S. Chaudhri.
Epidemiology of gastrointestinal nematodes of sheep
and goats in Haryana, India. Vet. Parasitol, 24: 117-27,
1987.
[18] Charles, T.P. Seasonal prevalence of gastrointestinal
nematodes of goats in Pernambuco state, Brazil. Vet.
Parasitol., 30: 335-343, 1989.
[19] Van Aken, D., J. De Bont, J. Vercruysse and P. Dorny.
Gastrointestinal nematode infections in a goat breeding
farm in North-Western Sri Lanka. Trop. Anim. Hlth.
Prod., 22: 231-238, 1990.
[20] Pandey, V.S., H. Ouhelli, A. Dakkak and J. Cabaret.
Epidemiology of gastrointestinal helminths of sheep in
the Rabat area of Morocco. Annales-de-Recherches-
Veterinaires, 21: 259-266, 1990.
[21] Jacquiet, P., F. Colas, J. Cabaret, M.L. Dia, D. Cheikh
and A. Thiam. Dry areas: An example of seasonal
evolution of helminth infection of sheep and goats in
southern Moauritania. Vet. Parasitol., 56: 137-148,
1995.
Sci.Int.(Lahore),25(2),305-309,2013 ISSN 1013-5316; CODEN: SINTE
309
[22] Dorny, P., C. Symons, A. Jalila, J. Vercruysse and R.
Sani. Stronglye infections in sheep and goats
under the traditional husbandry system in Peninsular
Malaysia. Vet. Parasitol., 56: 121-136, 1995.
[23] Asanji, M.F. and M.O. Williams. Variables affecting
population dynamics of gastrointestinal helminth
parasites of small farm ruminants in Sierra Leone. Bull.
Anim. Hlth. Prod. Afr., 35: 308-313, 1987.
[24] Pal, R.A. and M. Qayyum. Breed, age and sex-wise
distribution of gastro-intestinal helminths of sheep and
goats in and around Rawalpindi region. Pak. Vet. J.,
12: 60-63, 1992.
[25] Gulland, F.M.D and M. Fox. Epidemiology of
nematode infections of Soay sheep (Ovis aries L.) on
St Kilda. Parasitol., 105: 481-492, 1992.
[26] Maqsood, M., Z. Iqbal and A.H. Chaudhry. Prevalence
and intensity of haemonchosis with reference to breed,
sex and age of sheep and goats. Pak. Vet. J., 16: 41-43,
1996.
[27] Jorgensen, L.T., D.M. Leathwick, W.A.G. Charleston,
P.L. Godfrey, A. Vlassoff and I.A. Sutherland.
Variation between hosts in the developmental success
of the free-living stages of trichostrongyle infections of
sheep. Int. J. Parasitol., 28: 1347-1352, 1998.
[28] Komoin, Oka. C., J. Zinsstag, V.S. Pandey, F. Fofana
and A.N. Depo. Epidemiology of parasites of sheep in
the southern forest zone of Coted'Ivoire. Revue-
d'Elevage-et-de-Medecine-Veterinaire-des-Pays-
Tropicaux, 52: 39-46, 1999.
[29] Valcarcel, F. and C. Garcia Romero. Prevalence and
seasonal pattern of caprine trichostrongyles in a dry
area of central Spain. J. Vet. Med. Series B., 46: 673-
681, 1999.
[30] El-Moukdad, A. R. Helminths of cattle in Syria.
Angewandte Parasitologie, 20: 11-16, 1979.
[31] Iqbal, N. C., M. S. Durrani and A. Tariq. The incidence
of gastrointestinal parasite in buffalo and cattle of Azad
Kashmir. Pak. Vet. J., 4: 60-61, 1984.
[32] Mourad, M. I., I. S. A. Abdullah and T. E. Allowy.
Comparative study on the gastrointestinal parasitism of
cattle & buffalo with special reference of
haematological changes at Assiut Governorate. Assiut
Vet. Med. J., 15: 163-166, 1985.
[33] Pal, R. N. and P. Balakrishnan. Helimintiasis in
ruminants. J. Andaman Sci. Assoc., 3: 8-13, 1987.
[34] Anwar, A. H., C. S. Hayat and M. I. Amir. Prevalence
of gastro intestinal helminthiasis and comparative
efficacy of anthelmintics in parasitized buffalo calves.
Pak. Vet. J., 16: 160-163, 1996.
[35] Motahar, M. H. Examination of gastrointestinal
helminth in livestock grazing in grassland of
Bangladesh. Korean J. Parasitology, 38: 187-190,
2000.
[36] Grant, J.L. The epizootiology of nematode parasites of
sheep in a high-rainfall area of Zimbabwe. J. South
African Vet. Assoc., 52: 33-37, 1981.
[37] Iqbal, M. M., Survey of gastrointestinal parasites in
buffaloes in Faisalabad & evaluation of efficacy of
Alendazole against these infections. M.Sc Thesis, UAF.
Deptt. Vet. Parasitology, Univ. of Agriculture,
Faisalabad., 1993.
[38] Connan, R.M. The effect of host lactation on a second
infection of Nippostrongylus brasiliensis in rats.
Parasitol., 64: 229-233, 1972.
... The present study in cattle is lower than studies by Raza et al., (2010) in Pakistan, Awraris et al., (2012) who observed that the infection rate of T.vitulorum was (37.50%) and (57%) respectively. On the other hand, results by Raza et al., (2013) showed that the infection rate was (15%) and Bharathi and Kumar, (2017) revealed that the infection rate was (16.17%), which lower than the present study. In buffaloes, the infection rate of T.vitulorum was lower than the previous report by Raza et al., (2010) in Pakistan who reported that the infection rate was (63.83%). ...
... In the current study, the infection rate was (52.8%), (48.84%), (34.32%) and (27.27%) in cattle, buffaloes, sheep, and goats respectively, the difference between species of highly significant importance (p<0.01). This result in cattle is relatively higher than studies by and Raza et al., (2013) from Pakistan and Tulu and Lelisa, (2016) from Ethiopia with an infection rate ( 51%) and (50.08%) respectively, but the current findings were lower than the infection rate by Ntonifor et al., (2013) in Cameroon who found that the infection rate was ( 56.7%), (64%) in Bangladesh by Chowdhury et al., (2017) and (74.3%) in Nigeria by Umar et al., (2018). Current findings in buffaloes are low in compared to the infection rate (54.47%) by Deeba et al., (2019) in Pakistan, (64.67%) in India by Patel et al., (2015), and (85.01%) in Bangladesh by Alam et al., (2016), but the present study is higher than studies by Saha et al., (2013) in India and Ahmad et al., (2020) in Bangladesh with an overall prevalence (39.6%) and (36.47%) respectively. ...
... These findings in cattle agree with previous findings by Rashid et al., (2015) in Bangladesh and Maharana et al., (2016) in India who reported that females were highly infected than males. On the other hand, these findings contrast with the previous studies by Raza et al., (2013) in Pakistan, Marskole et al., (2016) in India, Tulu and Lelisa, (2016) in Ethiopia who reported that males were highly infected than females. Also in buffaloes and goats, the present study revealed that female animals were highly infected than males, but of no significant importance (p>0.05). ...
Article
Full-text available
Prevalence and seasonal variations of some helminth parasites was conducted in (cattle, buffaloes, sheep, and goats) from Sohag Governorate, Egypt with overall prevalence (44.64%). Infection rate was in cattle (52.78%), in buffaloes (48.84%), in sheep (34.32%) and in goats (27.27%). Fasciola spp. was higher in sheep (6.51%) while the lowest infection rate was in goats (3.64%). For Paramphistomum spp., the highest infection rate was in buffaloes (1.7%) and the lowest was in cattle (0.8%). For Moniezia spp. sheep had the highest infection rate (22.49%) while the lowest infection rate was in buffaloes (19.2%). For Toxocara vitulorum, cattle had the highest infection rate (31.4%) while the lowest was in buffaloes (26.8%). In addition, for Strongyle type eggs, the highest infection rate was in cattle (8.1%) while the lowest was in goats (1.8%). For Strongyloides spp. eggs prevalence rates in cattle and sheep were (0.8%) and (0.6%) respectively. Trichuris spp. eggs were found only in sheep with an infection rate (0.6%). Significantly cattle and buffaloes at age >3y were the highly infected group, but for sheep and goat, age group at age 1-3y were the highly infected group. Seasonally, winter was significantly with highest infection rate in both cattle and sheep, but summer season was significantly with highest infection rate in buffaloes and goats. Strongyle type eggs were cultured to detect several larvae including (110 cattle, 59 buffaloes, and 56 sheep) and the following larvae were detected (Oesophagostomum radiatum, Cooperia onchophora Trichostrongylus axei, Ostertagia ostertagi, Cooperia curticei, Ostertagia circumcincta, and Haemonchus contortus).
... The present study in cattle is lower than studies by Raza et al., (2010) in Pakistan, Awraris et al., (2012) who observed that the infection rate of T.vitulorum was (37.50%) and (57%) respectively. On the other hand, results by Raza et al., (2013) showed that the infection rate was (15%) and Bharathi and Kumar, (2017) revealed that the infection rate was (16.17%), which lower than the present study. In buffaloes, the infection rate of T.vitulorum was lower than the previous report by Raza et al., (2010) in Pakistan who reported that the infection rate was (63.83%). ...
... In the current study, the infection rate was (52.8%), (48.84%), (34.32%) and (27.27%) in cattle, buffaloes, sheep, and goats respectively, the difference between species of highly significant importance (p<0.01). This result in cattle is relatively higher than studies by and Raza et al., (2013) from Pakistan and Tulu and Lelisa, (2016) from Ethiopia with an infection rate ( 51%) and (50.08%) respectively, but the current findings were lower than the infection rate by Ntonifor et al., (2013) in Cameroon who found that the infection rate was ( 56.7%), (64%) in Bangladesh by Chowdhury et al., (2017) and (74.3%) in Nigeria by Umar et al., (2018). Current findings in buffaloes are low in compared to the infection rate (54.47%) by Deeba et al., (2019) in Pakistan, (64.67%) in India by Patel et al., (2015), and (85.01%) in Bangladesh by Alam et al., (2016), but the present study is higher than studies by Saha et al., (2013) in India and Ahmad et al., (2020) in Bangladesh with an overall prevalence (39.6%) and (36.47%) respectively. ...
... These findings in cattle agree with previous findings by Rashid et al., (2015) in Bangladesh and Maharana et al., (2016) in India who reported that females were highly infected than males. On the other hand, these findings contrast with the previous studies by Raza et al., (2013) in Pakistan, Marskole et al., (2016) in India, Tulu and Lelisa, (2016) in Ethiopia who reported that males were highly infected than females. Also in buffaloes and goats, the present study revealed that female animals were highly infected than males, but of no significant importance (p>0.05). ...
Article
Full-text available
Prevalence and seasonal variations of some helminth parasites was conducted in (cattle, buffaloes, sheep, and goats) from Sohag Governorate, Egypt with overall prevalence (44.64%). Infection rate was in cattle (52.78%), in buffaloes (48.84%), in sheep (34.32%) and in goats (27.27%). Fasciola spp. was higher in sheep (6.51%) while the lowest infection rate was in goats (3.64%). For Paramphistomum spp., the highest infection rate was in buffaloes (1.7%) and the lowest was in cattle (0.8%). For Moniezia spp. sheep had the highest infection rate (22.49%) while the lowest infection rate was in buffaloes (19.2%). For Toxocara vitulorum, cattle had the highest infection rate (31.4%) while the lowest was in buffaloes (26.8%). In addition, for Strongyle type eggs, the highest infection rate was in cattle (8.1%) while the lowest was in goats (1.8%). For Strongyloides spp. eggs prevalence rates in cattle and sheep were (0.8%) and (0.6%) respectively. Trichuris spp. eggs were found only in sheep with an infection rate (0.6%). Significantly cattle and buffaloes at age >3y were the highly infected group, but for sheep and goat, age group at age 1-3y were the highly infected group. Seasonally, winter was significantly with highest infection rate in both cattle and sheep, but summer season was significantly with highest infection rate in buffaloes and goats. Strongyle type eggs were cultured to detect several larvae including (110 cattle, 59 buffaloes, and 56 sheep) and the following larvae were detected (Oesophagostomum radiatum, Cooperia onchophora Trichostrongylus axei, Ostertagia ostertagi, Cooperia curticei, Ostertagia circumcincta, and Haemonchus contortus).
... Direct, indirect, and copro-culture techniques were implied to examine the worms. The sample analysis revealed a 51% overall prevalence of helminth and a 21% prevalence of nematodes were recorded (Raza et al., 2013a). ...
... Esto además explica que la infección crónica es más común en cabras que en ovejas, ya que la fasciolosis crónica se desarrolla más lentamente después de la ingestión de un bajo número de metacercarias durante periodos largos, en tanto que los ovinos tienden a ingerir altas cantidades de metacercarias por el tipo de comportamiento alimentario, lo cual genera una infección aguda (Kahl et al., 2021 Los machos fueron los más sero-positivos en este trabajo; sin embargo, el sexo no se estableció como factor de riesgo. Si bien algunos estudios indican que los machos son más susceptibles en comparación con las hembras, posiblemente por diferencias en el manejo de estos en las producciones de pequeños rumiantes (Mir et al., 2013;Raza et al., 2013), en general se acepta que las hembras suelen ser más susceptibles por el estrés de la preñez, donde se compromete su sistema inmune, haciéndolas más susceptibles a infecciones parasitarias (Magaji et al., 2014;Najib et al., 2020). Es importante destacar que, en este estudio, la población de machos era considerablemente más pequeña en comparación con el número de hembras muestreadas, lo que podría haber influido en la tasa de seroprevalencia y en la detección de un posible factor de riesgo asociado al sexo. ...
Article
Full-text available
El objetivo del estudio fue determinar la seroprevalencia de Fasciola hepatica por medio de ELISA indirecto en ovinos y caprinos de Boavita (Boyacá, Colombia). Se realizó un estudio descriptivo de corte transversal con muestreo aleatorio simple. Se colectaron 297 muestras de sangre de ovinos y 337 de caprinos de diferentes grupos raciales y etarios. Los sueros fueron analizados mediante la técnica ELISA indirecta con el kit comercial ELISA BIO K 211 - Monoscreen AbELISA F. hepatica. Adicionalmente se realizó una encuesta epidemiológica. La seroprevalencia de F. hepatica fue de 67.34% (200/297) en ovinos y de 59.94% (202/337) en caprinos. Asimismo, la seroprevalencia fue mayor en los machos (ovinos: 77.78%. 21/27; caprinos: 63.89%, 23/36), en ovinos mayores de 3 años (83.33%, 50/60) y en caprinos menores de 1 año (69.77%, 60/86), así como en los de raza criolla (ovinos: 69.84%; caprinos: 61.79%). Los ovinos mayores de 3 años se determinaron como factor de riesgo, en tanto que en los caprinos las variables raza criolla y el pastoreo extensivo se identificaron como factores de riesgo. El estudio demuestra una alta seropositividad de la enfermedad en la zona.
... Direct, indirect, and copro-culture techniques were implied to examine the worms. The sample analysis revealed a 51% overall prevalence of helminth and a 21% prevalence of nematodes were recorded (Raza et al., 2013a). ...
Article
Full-text available
Livestock plays an important role in the national economy and has a significant share in the gross domestic product of Pakistan. Parasitic diseases and worm infestations negatively affect their health, production, and reproductive performance. In addition, parasitic infestation in livestock reduces gross production values and renders huge economic losses globally. Among the parasites, the most important are nematodes. They are distributed worldwide and affect all kinds of livestock. This review aimed to elaborate on the main gastrointestinal nematodes, their mode of action, impacts on livestock and their control (physical, chemical or biological) strategies. Common examples of nematode worms infesting the livestock are Ascaris, and Oesphagostomum. The gastrointestinal nematodes are detrimental to the animals' health. Nematodes primarily affect animals' feed consumption and efficiency, and severe ailments result in the death of the affected animals. The production and health losses primarily depend on the age of the animals, the degree of severity of worm infestation, epidemiology pattern of the parasites, management strategies of the flocks, and ecoclimatic conditions which are favorable for the worm's infestation. To minimize these issues, farmers should be educated on the importance of intensive livestock management and environmental sanitation, as well as strategic deworming of cattle using efficient broad-spectrum anthelmintics, biological control of the parasites, and breaking their life cycle and intermediate hosts.
... Dissimilarities found in sex-wise occurrence, Females of domestic ruminants were slightly lowered than males in Nigeria and Pakistan (Njoku-tony and Nwoko, 2009;Raza et al., 2013). In this study, the appropriate information of incidence of G. crumenifer and other parasites existing infection along with seasonal trends and geographical distribution is highly essential and greatly infection found in goats among other domestic ruminants ...
Article
Full-text available
Present study found the main prevalence of amphistome Gastrothylax crumenifer infection in domestic ruminants like goats of the Chittorgarh district. The study was conducted in Chittorgarh district from January 2019 to December 2020. The 450 rumen of slaughtered goats from different slaughtered houses were examined, out of 450 goats, 375 goats were found infected highly with Gastrothylax crumenifer amphistome. The infection was also found throughout the year in different seasons, in summer at 31.11%, winter at 45.45% and maximum in monsoon 80.4%. Age-wise prevalence showed the highest infection in young goats and lowest in growing goats. The present investigation shows that the intensity or severity of infection of amphistome G. crumenifer which produces a paramphistomiasis in the goats. Infection of the amphistome parasite in goats leads to great economic losses by causing mortality in domestic ruminants.
... The larvae were identified on the basis of key provided by Soulsby 1982, Taylor et al. 2007, Van Wyk and Mayhew 2013, and were identified as Haemonchus sp. as major contributor to the nematode population followed by Trichostrongylus sp., Oesophagostomum sp. and Cooperia sp. in the decreasing order of prevalence. Various researchers in their respective studies on cattle population have encountered these nematodes from Rajasthan (Monika et al. 2017, Renwal et al. 2017, different parts of India (Jithendran andBhat 1999, Murleedharan 2005) as well as abroad (Borgsteede et al. 2000, Hailu et al. 2011, Asif Raza et al. 2013. The larvae of Haemonchus sp., Cooperia sp., and Trichostrongylus sp. were observed throughout the study period while Oesophagostomum sp. was found dominant in summer season. ...
Article
The aim of this study was to determine the prevalence and risk factors of gastrointestinal helminthic infections in dairy animals of internal drainage dry zone of Rajasthan, India. A total of 609 fecal samples were examined from September 2016 to August 2017. Out of them, 295 (Buffalo: 111, Cattle:184) were found positive with an overall prevalence of 48.44% for different gastrointestinal helminthic infections. The study revealed strongyles as the most dominant infection (44.99%) followed by Strongyloides sp. (6.90%). Seasonal dynamics revealed a highly significant statistical seasonal variation (p<0.05) with maximum infection in rainy season (60.10%) whereas, a non-significant statistical difference in district wise prevalence was reported with the highest prevalence rate in Nagaur district (54.97%). Multivariate binary logistic regression model revealed positive association of summer (B=0.83) and rainy seasons (B=1.39) when compared to winter season whereas, association was reported positive in Nagaur (B=0.27) and negative in Jhunjhunu (B=-1.42) and Churu (B=-0.15) districts when compared to Sikar district. Similarly, a negative association in crossbred (B=-0.75) and buffaloes (B=-0.53) as compared to native animals was reported in the study. Quantitative analysis presented a mild to moderate gastrointestinal parasitic infection in terms of EPG (eggs per gram of feces) ranged from 100-400 (228.57±42.06) and 100-300 (166.67±33.33) for stongyles and Strongyloides sp. respectively. No fluke infection was reported in the dairy animals of the study area during the study period. Coproculture examination exhibited Haemonchus as the most predominant nematode genus, followed by Oesophagostomum sp., Strongyloides sp., Trichostrongylus sp. and Cooperia sp. in the decreasing order of prevalence. The current investigation may be used to formulate effective control strategies against gastrointestinal helminthic infections in the dairy animals of the region.
... This finding confirmed with the results of Umar et al. [3] and Telila et al. [27], who reported a higher occurrence of G.I. helminths in the male than female animals. Similarly, earlier findings of Ola-Fadunsin [34] and Raza et al. [35] also recorded that male cattle were more likely to be infected with G.I. helminths than their female counterpart. The reason given was since male animals are more aggressive when feeding, and this will increase their chances to pick-up more G.I. helminths eggs on the pasture. ...
Article
Full-text available
A Cross-sectional Study was carried out to determine the prevalence of gastrointestinal (G.I.) helminths parasites in slaughtered cattle at Azare abattoir, Katagum Local Government Area, Bauchi State, North-Eastern Nigeria. One hundred and twenty faecal samples were examined using the floatation and sedimentation method. Out of the total samples tested, G.I. helminths infections were detected in 62samples tested, giving an overall prevalence of 51.6%. Class nematodes are the most diverse class (56.5%) and then followed by trematodes (35.5%), while cestodes are the least prevalent (8.1%). There was a statistically significant difference in P-value >0.05. The sex revealed that males (52.6%) are more susceptible to G.I. helminths infection than females (50.0%) even though there is no statistical difference at P-value >0.05. However, the prevalence of G.I. helminths to age revealed a statistical difference at P-value >0.05, where the young have the highest prevalence of 59.5%. The Red Bororo breeds had the highest prevalence of 75%, while the least was recorded in White Fulani and Sokoto Gudali, 40% each. There was a statistically significant difference at P-value >0.05. This study revealed that Fasciola spp (15%) is the most prevalent G.I. helminths parasites detected, followed by Oesophagostomum spp (11.7%); Haemonchus spp (9.2%); Strongyloides spp (8.3%), Schistosoma spp (3.3%); and Moniezia spp (1.67%). Our findings from the present study revealed a high prevalence of G.I. helminths species affecting cattle in Azare and Nigeria as a whole. Therefore, there is a great need for proper advocacy on the need for appropriate management, regular deworming practices, and improved cattle hygiene to boost animal production. This will help in curbing great lost to Nigeria's economy and the world in general.
Conference Paper
Full-text available
Gastrointestinal helminthes have been recognized as a major constraint to production of cattle in developing countries. A cross-sectional study was carried out to determine the prevalence of gastrointestinal parasitic helminthes of cattle in Bwari abattoir, F.C.T Abuja. Systematic random sampling of cattle slaughtered was used and analysed using sedimentation and floatation methods, fecal samples per rectum from 200 animals were examined between May and June 2019. Overall, 103 (51.5%) of the animals were positive for gastrointestinal parasitic helminths egg, with Strongyle-type egg infection being the highest 59 (29.50%) and Trichuris trichuria being the lowest with a prevalence of 1 (0.5%). Among the cattle examined, the White Fulani breed was the most infected (57.25%; 79/138). Furthermore, female cattle and cattle with moderate body condition showed more infection of parasitic helminthes with prevalence rates of 54.27% and 54.44% (89/164; 92/169) respectively. Chi square analysis revealed that there was no significant difference in parasitic infection amongst the sex and body condition of the cattle examined at p > 0.05. The study revealed that the majority of the cattle slaughtered in Bwari abattoir, F.C.T, Abuja had a high prevalence rate of gastrointestinal parasitic helminthes infestation and recommends that strategic deworming of animals be done using appropriate anthelminthic chemotherapy.
Article
Calves infected with gastrointestinal nematodes can spread diseases to other livestock in a new environment, causing a decrease in quality, and financial losses for farmers. This study aims to determine the prevalence and intensity of infection, as well as the gastrointestinal nematodes infecting Bali cattle calves at the Beringkit Livestock Market, Badung Regency. The study used a floatation method to identify worm egg morphology and continued with the McMaster method to determine infection intensity. Out of 100 fecal samples examined, 65 samples were found positive for gastrointestinal nematode infection, resulting in a prevalence of 65% infection among Bali cattle calves at the Beringkit Livestock Market, Badung Regency. The identified nematodes were strongyle-type worms (64%) with an infection intensity of 203 ± 384 EPG, Strongyloides papillosus (10%) with an infection intensity of 100 ± 89 EPG, and Toxocara vitulorum (9%) with an infection intensity of 155 ± 287 EPG. It is concluded from this study that the prevalence of gastrointestinal nematode infections in Bali cattle calves at the Beringkit Livestock Market, Badung Regency was high with infection intensity falling into the mild category. Regular and continuous deworming is necessary as a control and prevention measure for gastrointestinal nematode infections in Bali cattle calves.
Article
The present study was carried out to contribute to the knowledge of the epidemiology of gastrointestinal nematode infections in milking ewes raised under semi-intensive management conditions in León province (NW Spain). A total of 779 faecal samples from 368 dairy sheep flocks of Churra and Churra × Assaf breeds, were analyzed during April 1991–March 1993 for gastrointestinal nematodes. These flocks came from 6 areas located in the south-east of León province. From the total faecal samples studied, 87.9% were positive to gastrointestinal nematodes, with a mean egg counts of 134.3 eggs per gram (epg), and a range of 0 to 2050 epg. No overall significant differences were found between different areas regarding to the prevalence of infected flocks. Data showed that faecal egg output was positive all year around but showed a two-peak pattern. The first and higher significant peak appeared during late winter to early spring (March) and the second maximum in mid summer (August). A relationship was found between climate conditions and the pattern of faecal egg output. The prevalence of infection showed a significant seasonal difference (chi-square = 7.93; P = 0.047). In conclusion, environmental factors affected the prevalence and intensity of gastrointestinal infection under semi-intensive management conditions. This study states the present knowledge of the epidemiology of gastrointestinal parasitism in sheep in León and may lead to improve application of existing control strategies.
Article
The epidemiology of nematode infections of Soay sheep on the island of St Kilda over a period of 2 years (August 1988-August 1990) spanning a host population crash is described. Infective larvae (L3) levels on pasture were high (2422 +/- 365 L3/kg D.M. grass in midsummer 1988) when host population density was high, decreasing after the sheep population declined by 70% in early 1989 (601 +/- 14 L3/kg D.M. in midsummer 1989). The availability of infective larvae to sheep increased during the winter of 1988-1989, probably as a result of concentration of existing larvae on grass as vegetation was destroyed by bad weather and overgrazing. Increased availability of pre-parasitic stages was accompanied by a marked increased in faecal egg counts from sheep of all ages and both sexes. Prevalence and intensity of infection (faecal egg counts) were higher in males than females throughout the 2-year study (chi 2 = 208.3, P < 0.005 and F1, 2000 = 304, P < 0.001 respectively), except during the lambing periods, and decreased with age in both sexes. Changes in prevalence and intensity of strongyle infections were associated with changes in host population density. Prevalence and intensity of Dictyocaulus filaria larvae in faeces increased during the host population crash. Infection intensity decreased with age (F1, 203 = 44.02, P < 0.001) and was higher in males than females (F1, 203 = 13.45, P < 0.001).
Article
The epidemiology of gastrointestinal helminths of sheep on permanent pastures in Morocco was studied by monthly examination of faeces of ewes for helminth eggs and by use of batches of 3 tracer lambs each month from December 1979 to November 1980. The main helminth genera encountered were Teladorsagia, Haemonchus, Trichostrongylus and Moniezia, with Nematodirus, Cooperia, Oesophagostomum and Trichuris occasionally recorded. The faecal egg counts of ewes showed 2 peaks; the first in March due to the acquisition of larvae during the rainy season and periparturient rise, the second in October probably due to maturation of inhibited larvae. The worm burdens of tracer lambs showed that there was a gradual accumulation of nematodes from December, reaching a peak in May; an absence of infection in July and August during the dry period, and a second peak in November. Infection by Moniezia was higher during the dry season.
Article
Faecal egg counts were used to study patterns of nematode infestation of adult female goats and their offspring according to season, pregnancy and lactation or age on a goat farm (n = 2000) in north-western Sri Lanka. Average rainfall in the area is 825 mm and temperature is between 23 and 33 degrees C throughout the year. The only nematode species present on the farm were Haemonchus contortus and Oesophagostomum columbianum. In adult females the faecal egg output was not influenced by season and no significant periparturient rise was observed. In kids the egg counts rose from the third month of age onwards and reached the same levels as the adults by the fourth month. Post-mortem studies on a neighbouring farm indicated that hypobiosis was not present.
Article
During each of 36 1-month periods from April 1979 to March 1982, 3-4 goats selected from typical farms were necropsied and examined for gastrointestinal nematodes. The goats were male, 12 months old, born on the farm and raised without any anthelmintic application. At the beginning of each month, from April 1981 to March 1982, three 12-month-old male goats shown to be free of gastrointestinal nematodes after anthelmintic treatment were grazed with a flock of naturally infected goats (tracer goats). At the end of each month, these goats were placed on a cement-floored pen and were maintained there for 4 weeks prior to necropsy and examination for gastrointestinal nematodes. Every goat examined was found to be parasitized by more than one species of nematode. Haemonchus contortus, Strongyloides papillosus and Oesophagostomum columbianum were the most prevalent nematodes found. Total worm burdens present in the farm animals were highest during late rainy/early dry season (March-June) and lowest in mid-rainy season (January-February). The acquisition of nematodes by tracer goats occurred mainly from mid-rainy to early dry season (January-June).
Article
Epidemiological studies on some gastrointestinal nematodes of sheep and goats in Karnal, Ambala and Rohtak districts of Haryana (India) revealed that Haemonchus contortus and Trichostrongylus spp. were responsible for parasitic gastroenteritis in these hosts. The adult parasites persisted in the host throughout the year and there was no indication of hypobiosis. The maintenance of the parasite population depended on a continuous cycle of infection between the host and the pasture. The agroclimatic conditions of the districts revealed that, in general, favourable weather conditions for the development and survival of the free-living stages of the parasites existed all year round.
Article
Rats were infected with 1000 larvae at the time of mating and they were given a second infection while suckling a new-born litter some 3½ weeks later. Although they did have significantly more worms than immune controls such rats were nevertheless highly resistant to challenge with infective larvae. However, when challenged with adult worms, immunized lactating rats were unable to eliminate the second infection. That the failure of self-cure in this case was not because adult worms are less antigenic in lactating rats was shown in the third experiment. Lactating rats were immunized by infection either with adult worms only or with larvae allowed to complete their life-cycle. When subsequently challenged with infective larvae during the same lactation, both groups were equally resistant. It is therefore concluded that in lactating rats the gut phase of N. brasiliensis infection is in some way protected from the self-cure mechanism. This may be due either to absence of an essential factor operating late in the process, or to the presence of a potentiating factor which allows the worms to survive. The author would like to thank Professor W. I. B. Beveridge in whose Department this work was carried out, and the Agricultural Research Council for their financial assistance. It is also a pleasure to acknowledge the technical assistance of Mr J. A. Wilson and Mr P. W. Holmes.