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Oestrus ovis, the sheep 'nasal bot fly', somewhat looks like a honey bee, has a rudimentary mouth parts and do not feed. The larva of the sheep nasal fly is responsible for causing a condition in sheep and goat called nasal myiasis, oestriosis or 'false gid'. The disease occurs when adult fly deposit first larvae (L1) into the nostrils of its host. The larvae develop into L2 and L3 in the nasal cavities and sinuses in due course. Sneezing and nasal discharges are the major clinical signs seen in infected animals. The pathogenic reaction occurs when the larvae irritate the mucosa with their spines and hooks during their development and also due to an allergic reaction induced by molecules excreted/secreted by the larvae. Sometimes damage of the skulls of the bones and injury to the brain occur to such an extent that signs of high-stepping gait and in-coordination suggesting the animal suffers from Coenurus cerebralis infection and hence the infection is also called false gid. Keeping in view the importance of the fly, the morphology, biology, pathogenesis, immunological reaction and various control measures of Oestrus ovis are discussed in this review.
International Journal of Medical, Pharmacy and Drug Research (IJMPD) [Vol-2, Issue-4, Jul-Aug, 2018] ISSN: 2456-8015 Page | 48
Nasal Myiasis in animals due to Oestridae - A
Mini Review
Gautam Patra1*, Papia Biswas2, Ana Sahara3, Parthasarathi Behera4,
Subhamoy Ghosh1, Ajit kumar4, S.K. Borthakur1, Seikh Sahanawaz Alam5,
and Apurba Debbarma6
1Department of Veterinary Parasitology; 2Department of Veterinary Public Health and Epidemiology; 3Department of
Veterinary Parasitology, Gadjah Mada University, Yogyakarta, Indonesia.
4Department of Veterinary Parasitology; WBUAFS, Kolkata-37, West Bengal, India.
5District Microbiologist, Malda Medical College & Hospital, Malda, West Bengal, India.
6Department of Veterinary Parasitology, College of Veterinary Sciences & Animal Husbandry, R.K. Nagar, Agartala,
Tripura, India.
*Corresponding author: Gautam Patra, Department of Veterinary Parsitology, College of Veterinary Sciences and Animal
Husbandry, Selesih, Aizawl, India. Tel: +91 8582859415; E-mail:
Abstract Oestrus ovis, the sheep ‘nasal bot fly’,
somewhat looks like a honey bee, has a rudimentary
mouth parts and do not feed. The larva of the sheep nasal
fly is responsible for causing a condition in sheep and
goat called nasal myiasis, oestriosis or ‘false gid’. The
disease occurs when adult fly deposit first larvae (L1) into
the nostrils of its host. The larvae develop into L2 and L3
in the nasal cavities and sinuses in due course. Sneezing
and nasal discharges are the major clinical signs seen in
infected animals. The pathogenic reaction occurs when
the larvae irritate the mucosa with their spines and hooks
during their development and also due to an allergic
reaction induced by molecules excreted/secreted by the
larvae. Sometimes damage of the skulls of the bones and
injury to the brain occur to such an extent that signs of
high-stepping gait and in-coordination suggesting the
animal suffers from Coenurus cerebralis infection and
hence the infection is also called false gid. Keeping in
view the importance of the fly, the morphology, biology,
pathogenesis, immunological reaction and various
control measures of Oestrus ovis are discussed in this
Keywords Oestrus ovis; morphology; biology;
immunopathology; control measures.
Oestrus ovis which is commonly called ‘sheep nasal fly’
or ‘nas al bot fly’, is res pons ible for s evere economic
losses in livestock across the globe (El-Tahawy et al.
2010). The larval phases (parasitic) of the fly irritate the
nasal mucosa with their spines and hooks while feeding to
support their growth and development (Cepeda-Palacios
et al. 1999; Tabouret et al. 2003). The migratory larvae
even penetrates and erode the dorsal turbinate bones,
frontal sinuses and occasionally the skull bones while
entering into the cerebral cavity causing ‘false gid’
(Taylor et al. 2016).
Human in close contact with livestock, sheep
particularly are at greater chance to become accidental
hosts for the O. ovis larvae. So the disease is also have
public health importance (Cepeda-Palacois 2001; Einer
and Ellegard 2011; Hummelen et al. 2011; Hoyer et al.
2016). Clinical signs are manifested by mucopurulent
nasal discharge, frequent sneezing and difficulty in
grazing, restlessness, incoordination and dyspnoea
(Dorchies et al. 1992; Dorchies and Alzieu 1997;
Dorchies et al. 2000). The pathogenic effects of oestriosis
are due to the damages in the nasal mucosa caused by the
cuticular spines and oral hooks but also by immunological
reactions of larval antigens (Jacquiet et al. 2005).
Important losses sue to O. ovis include upto 22% loss
body weight, 16% in wool production and 10% in milk
production (Shcherban 1973). The fly has cosmopolitan
in distribution where sheep and goats rear. They also
attack deer and occasionally horses, cattle, dogs and
human. The current method of oestriosis is based on
chemotherapy in sheep because no bait or traps are
available to control the free living adult fly (Cepeda-
Palocios and Scholl 2000b). Endectocides and fasciolicide
drugs such as closantel and nitroxynil are often used to
treat nasal myiasis in sheep and goats (Dorchies et al.
The purpose of this review is to discuss the
morphology, biology of Oestrus ovis together with
immunopathology caused by the larvae of this fly vis-à-
vis some of the controlling measures based on available
International Journal of Medical, Pharmacy and Drug Research (IJMPD) [Vol-2, Issue-4, Jul-Aug, 2018] ISSN: 2456-8015
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The genus Oestrus contains four species O.
aureogentatus, O caucacicus, O ovis and O. variolasus.
O. aureogentatus and O. variolosus are found throughout
Africa, south of the Sahara and O. caucacicus is present
in domestic and wild animals of the Caucasus regions and
central Asia. However, O. ovis is found in all sheep
farming areas of the world. The adult fly is about 13-15
mm in length and grey in colour with black spots on the
thorax and abdomen and somewhat resembles a bee (Fig.
1). The whole body is covered with light brown hair. The
mouthparts are vestigial. The head is broad with small
eyes. The segments of the antennae are small and the
arista bare. They have a yellow-brown head, with small
tubercles of equal size on the thorax and the yellow legs.
They possess yellow-veined wings which have a strongly
bent M vein joining the R4+5 veins before the wing
margin. It is an obligate parasite in sheep and goats in
many parts of the world.
The tiny first-stage larvae are white or slightly
yellow in colour and spindle in shape, 1-3 mm long with
relatively large cephaloskeleton which may be seen
during post-mortem by sawing the skull in half-
longitudinally (Fig. 2). They are provided with strongly
bent sclerites (gently curved mouth-hooks) and 22-25
terminal spines arranged in two groups. The third
segment contains a row of denticles on the dorsal side.
Ventrally the segments at their anterior margins show two
to three rows of spine and hair like structures. Laterally,
they have 22-25 hooks (Zumpt 1965).
The second instar larva is white in colour and
3.5-12 mm long with few weak denticles on the dorsal
side of the second segment, the median part of the post
anal bulge is spinulose, ventrally the segments are
provided with spines, the posterior peritremes are more or
less circular, the channels are indicated by distinct suture
(Zumpt 1965).
The mature larvae are about 2-3 cm long and
brown with transverse, dorsal blackish bands. The
anterior end is somewhat tapering but the posterior
surface has a flat surface. The larvae bear large, black oral
hooks, connected to an internal cephalopharyngeal
skeleton (Fig. 3) The dorsal surface is devoid of spines
while the ventral surface bears rows of small spines and
the black stigmatic plates are circular, with a central
ecdysial scar, and without a distinct suture (Zumpt 1965).
The prevalence and incidence are greatly varied
depending on climate and ecological factors. In temperate
countries the flies occur in late spring and summer
whereas in warm climate it can infest the sheep
throughout the year. The prevalence and distribution of
the fly is shown in Table no. 1.
Table.1: Prevalence rates of Oestrus ovis infestation in
different countries
Rate (% )
Saudi Arabia
Alahmed et al.,
Pathak, 1992;
Godara et al., 2010
6 52
Pandey, 1989
10 100
Paney and Ouhelli,
Gebremedhin, 2011;
Bekele and Mukasa-
Mugerova, 1994
Gabaj et al., 1993
33.2 65
Dorchies et al., 2000
Abo-Shehada et al.,
Benakhla et al.,
Alcaide et al., 2003
Caracappa et al.,
Barroso et al., 2017
The life cycle of the sheep nasal fly is shown in figure 4.
The life cycle begins when the young larvae are deposited
by the adult flies. Each female can produce up to 500
larvae. Bart and Minar (1992) reported that many L1 are
destroyed in the nasal cavities during the hypobiotic
period. After being deposited the larvae crawl onto the
mucous membrane of the nasal passage where they spend
at least two weeks and are found attached to the mucous
membrane by means of oral hooks. First stage larvae are
deposited in packages directly into the nostrils with
accurate precision. Thermo sensible cuticular sensilia and
a quick mobility of the larvae allow them to overcome the
first defence reactions such as sneezing and rubbing
against close objects (Colwell and Scholl, 1995). It has
been reported that the rate of larval establishment is 0-
48% in sheep (Frugere et al. 2000) and 29-40% in goats
(Angulo-Valadez et al. 2009). It is known that better
water economy in goats leads to len humid noses than in
sheep. This higher humidity is more conducive for larval
survival in sheep than goats (Papodopoulos et al. 2010).
Inside the host’s nos e, the larvae either continue to grow
or hibernate in response to a combination of intrinsic
rhythms and external environmental stimuli. Temperate
countries, the first stage larvae hibernate but very high
temperature slows the growth rate (Yilma and Dorchies
1991). Limited information is available about second
stage larvae. They quickly develop into the sinuses of the
International Journal of Medical, Pharmacy and Drug Research (IJMPD) [Vol-2, Issue-4, Jul-Aug, 2018] ISSN: 2456-8015
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host and trigger a strong cellular reaction with infiltration
of mast cells and eosinophils. This stage relies on a high
protein diet which mainly they derive from mucus and
seroproteins by way of trypsin like enzymes (Tabouret et
al. 2003b). Finally the full grown larvae crawl out and
expelled by the sneezing of the host onto the ground
where they pupate. Under favourable environmental
conditions, the duration of the first, second and third
stages vary from 10-25 days, 7-15 days and 13-18 days,
respectively (Cepheda-Palacios 2002). Intrapuparial
metamorphosis occurs over 19-27 days before adult flies
Adults do not bear functional mouth parts and
therefore minimize the energy loss by localizing their
potential hosts and suitable mates with their large eyes.
They are swift fliers and since they do not feed, the
lifetime of adult is short and females emerge from the
puparium bear fully developed eggs which are ready to
fertilize (Taylor et al. 2016).
The intensity of local changes inoculated by O. ovis
larvae in the mucosa of the upper respiratory tract of the
host is not related to larvae density but Biggs et al. (1998)
suggested that any larval number above 10 is potentially
dangerous. The most significant lesions are seen in the
sinus and ethmoidal mucosa. In natural or artificial
infection, there is hyperplasia and abrasion of muco-
ciliary film (Dorchies et al. 2006). A strong cellular
response is elicited as many cells are positively marked as
Ki67 epitopes (Nguyen Van Khanh et al. 1998). Many
ultra-structural changes in the nasal sinus are due to a
combination of mechanical damage associated with
effects of secreted proteases from the larvae. These
changes increase the permeability of the mucosa allowing
the diffusion of antigenic/ excretory products through the
mucosa to come in close contact with the locally recruited
immune cells (Dorchies et al. 2006). Histopathological
data indicates pathogenesis of ovine oestrosis is due to
Type-I immediate hypersensitivity phenomenon. Many B
and T lymphocytes, phagocytic mononuclear cells
(PMC), eosinophils, mast cells and globule leucocytes
have been observed where larval moult occurs (Tabouret
et al. 2003b). Nasal myiasis also induces IgM and IgG
production in both sheep and goats (Suarez et al. 2005;
Angulo-Valadiz et al. 2008, 2009).
Clinical signs can be described into three
categories: fly strike, sinusitis and other consequences.
5.1. Fly strike
Fly activity causes great annoyance when attack sheep to
deposit larvae into the nostrils. The animals get nervous
and congregate together, keeping their noses deep inside
the fleece of the other sheep or close to the ground (Fig.
5, 6). Animals become restless and stop feeding. Goats
are less reactive because of their browsing habits (Hoste
et al. 2001).
5.2. Sinusitis
The irritation of the nasal mucosa caused by the oral
hooks and spines of the fly larvae manifests by nasal
discharge and sneezing. Sheep are agitated and the nasal
discharge occasionally become purulent tinged with blood
(snotty nose, Fig. 7). Sometimes erosion of the bone and
eventual injury to the brain with neurological signs
including ataxia, nystagmus, high stepping gaits and in-
coordination of movements may be misdiagnosed as C.
cerebralis infection. For this reason, the infection is also
called false gid.
5.3. Other consequences
In some breeds of sheep, neoplastic growth might be
found (Bergeaud et al. 1994). In some cases, interstitial
pneumonia with interstitial emphysema and pleural
adhesion has also been observed (Dorchies et al. 1993).
The objective of the treatment is to eliminate or at least
suppression of clinical signs and to limit the extension of
the endemic zone of the parasite. Sheep already infected
with nasal bot flies can be successfully treated with
several parasiticides. Ivermectin either as injectable form
or oral drenches have excellent curative effect and gives
protection against re-infestation after several weeks of
treatment (Bowman 2014). Roncalli (1984) reported that
larvae of O. ovis are highly susceptible to ivermectin at a
dose rate of 0.2 mg/Kg body weight. The efficacy of
eprinomectin at with 0.5 mg/Kg and 1 mg/Kg body
weight ranges from 83.5 100% (Hoste et al. 2004;
Habela et al. 2006).
Anthelmintics which are commonly used against
nasal bots include closantel nitroxynil and rafoxanide.
Closantel have a persistent effect on larvae and can give
protection to animals from reinfestation during fly season
(Dorchies et al. 1997).
Enhanced immune responses may have a
detrimental effect on O. ovis larvae led to immunological
trials against O. ovis in sheep using excreted/secreted
products and digestive tract protein extracts of third
instars by previous works (Frugere et al. 2000; Angulo-
Valadez et al. 2007). It was predicted that immunized
animals would develop humoral responses against such
antigens. The authors concluded that a reduction of 40%
mature larvae weight would reduce 38% adult population.
Further experiment is required to ascertain whether such
immunization can affect the adult population
The more general control measure includes
feeding in narrow troughs, the edges of which are
smeared with tar. This automatically tars the animals and
thus acts as a repellent (Bowmann 2014).
International Journal of Medical, Pharmacy and Drug Research (IJMPD) [Vol-2, Issue-4, Jul-Aug, 2018] ISSN: 2456-8015
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The authors are thankful to the Dean, College of
Veterinary Sciences and Animal Husbandry, Central
Agricultural University, Selesih, Aizawl, India for
providing necessary support.
[1] Abo-Shehada M N, Arab B, Mekbel R, Williams D
and Torgerson P R. 2000. Age and seasonal
variations in the prevalence of Oestrus ovis larvae
among sheep in northern Jordan. Preventive
Veterinary Medicine 47(3): 205-212.
[2] Alahmed A M I. 2002. Seasonal Prevalence of
Cephalopina titillator Larvae in Camels in Riyadh
Region, Saudi Arab. Gulf Journal of Scientific
Research 20(3): 161-164.
[3] Alcaide M, Reina D, Sanchez J, Fronter E and
Navarrete I. 2003. Seasonal variations in the larval
burden distribution of Oestrus ovis in sheep in the
southwest of Spain. Veterinary Parasitology 118:
[4] Angulo-Valadez C E, Cepeda-Palacios R, Ascencio
F, Jacquiet P, Dorchies P, Romero M J and Khelifa
R M. 2007. Proteolytic activity in salivary gland
products of sheep bot fly (Oestrus ovis) larvae.
Veterinary Parasitology 149: 117.
[5] Angulo-Valadez C E, Cepeda-Palacios R, Ascencio
F, Jacquiet Ph, Dorchies Ph, Ramirez-Orduna J M
and Lopez M A. 2009. IgG antibody response
against salivary gland antigens from Oestrus ovis
(Diptera: Oestridae) in experimentally and naturally
infected goats. Veterinary Parasitology 161: 356
[6] Angulo-Valadez C E, Scala A, Grisez C, Prevot F,
Bergeaud J P, Carta A, Cepeda-Palacios R, Ascencio
F, Terefe G, Dorchies Ph and Jacquiet Ph. 2008.
Specific IgG antibody responses in Oestrus ovis L.
(Diptera: Oestridae) infected sheep: associations
with intensity of infection and larval development.
Veterinary Parasitology 155: 257263.
[7] Anon. 2018.
Accessed on 24.01.2018.
[8] Anon. 2018.
Accessed on 25.01.2018.
[9] Anon.2018.
7247/391380222.jpg?1429746733Accessed on
[10] Anon.2018.
Accessed on 24.01.2018.
[11] Anon. 2018.
goats/sheep-nose-bot. Accessed on 24.01.2018.
[12] Anon. 2018.
M:&imgrc=u8bEltH1CxqkvM: Accessed on
[13] Barroso P, Ruiz-de-Ybáñez R, Martínez-Carrasco C,
Gens M J, Escribano F, Sánchez A and Pérez J M.
2017. First report of oestrosis in aoudad from
southeastern Spain. Parasitology Research 116(7):
[14] Bart A G and Minar J. 1992. Probability description
of regulation on the level of population and
individual in the host parasite system using Oestrus
ovis (Diptera: Oestridae) as an example. Folia
Parasitologica 39: 75- 83.
[15] Bekele T and Mukasa-Mugerwa E. 1994. Oestrus
ovis infection in Ethiopian highland sheep.
Veterinary Research Communications 18(6): 439-
[16] Benakhla A, Sedraoui S, Benouareth D E, Cabaret J
and Boulard C. 2004. Epidemiology of sheep
infection by Oestrus ovis in Algeria. Parasite 11(2):
[17] Bergeaud J P, Duranton C and Dorchies Ph. 1994.
L’œstros e ovine en Aveyron: Résultat d’une enquête
sur 1036 tes à l’abattoir de Rodez. Revue de
Médecine Vétérinaire 145(11): 863866.
[18] Biggs H C, Mcclain E, Muller G L, Anthonissen M
and Hare K M. 1998. A prediction model for strike
in the sheep nasal fly, Oestrus ovis, in Namibia.
Preventive Veterinary Medicine 33: 267282.
[19] Caracappa S, Rilli S, Zanghi P, Di Marco V and
Dorchies Ph. 2000. Epidemiology of ovine oestrosis
(Œstrus ovis Linne 1761, Diptera: Oestridæ) in
Sicily. Veterinary Parasitology 92: 233-237.
[20] Cepeda-Palacios R. 2002. Recent advances in
Oestrus ovis developmental biology and ecology.
Proceedings of the Workshop Mange and Miyasis in
Livestock (ed. by M. Good, M. J. Hall, B. Losson,
D. O’Brien and K. Pithan), pp. 16. 36 October
2001, European Commission COST action 833,
Ecole Nationale et´erinaire de Toulouse,
[21] Cepeda-Palacios R and Scholl P J. 2000b. Factors
affecting the larvipositional activity of Oestrus ovis
International Journal of Medical, Pharmacy and Drug Research (IJMPD) [Vol-2, Issue-4, Jul-Aug, 2018] ISSN: 2456-8015
www.aipublicat Page | 52
gravid females (Diptera: Oestridae). Veterinary
Parasitology 91: 9395.
[22] Cepeda-Palacios R, Avila A, Ramirez-Orduna R and
Dorchies Ph. 1999. Estimation of the growth
patterns of Oestrus ovis L. larvae hosted by goats in
Baja California Sur, Mexico. Veterinary
Parasitology 86: 119126.
[23] Cepeda-Palacios R, Monroy A, Mendoza M A and
Scholl P J. 2001. Testicular maturation in the sheep
bot fly Oestrus ovis. Medical and Veterinary
Entomology 15: 275280.
[24] Colwell D D and Scholl P J. 1995. Cuticular sensilla
on newly hatched larvae of Gasterophilus
intestinalis and Oestrus ovis. Medical and
Veterinary Entomology 9: 8593.
[25] Dorchies P. and Alzieu J P. 1997. L’oestrose ovine:
revue. Revue Medicine V´et´erinaire 148: 565574.
[26] Dorchies P, Alzieu J P, Yilma J M, Donat F,
Jeanclaude D and Chiarisoli O. 1992. Prevention de
l’oestrose ovine par deux ´ traitements au closantel
en cours d’et ´ e: appr ´ eciation clinique et
´parasitologique. Revue Medicine V´et´erinaire 143:
[27] Dorchies P, Tabouret G, Hoste H and Jacquiet P.
2006. Oestrinae hostparasite interactions. In:
Colwell D D, Hall M J R and Scholl P J (Eds.), The
Oestrid Flies. CABI Publishing, 359 pp.
[28] Dorchies Ph, Alzieu J P and Cadiergues M C. 1997.
Comparative, curative and preventive efficacies of
ivermectin and closantel on Oestrus ovis (Linné
1761) in naturally infected sheep. Veterinary
Parasitology 72: 179-184.
[29] Dorchies Ph, Bergeaud J P, Tabouret G, Duranton C,
Prevot F and Jacquiet Ph. 2000. Prevalence and
larval burden of Oestrus ovis (Linné 1761) in sheep
and goats in Northern Mediterranean region of
France. Veterinary Parasitology 88: 269-273.
[30] Dorchies Ph., Bergeaud J. P., Van Khanh N. and
Morand S. (1997) Reduced egg counts in mixed
infections with Oestrus ovis and Haemonchus
contortus: influence of eosinophils? Parasitology
Research 83, 727730.
[31] Dorchies Ph, Yilma J M and Savey J. 1993. Lung
involvement in ovine Oestrosis: prevalence of lung
abscesses and interstitial pneumonia. Veterinary
Record 133: 325.
[32] Einer H and Ellegård E. 2011. Nasal myiasis
by Oestrus ovis second stage larva in an
immunocompetent man: case report and literature
review. The Journal of Laryngology & Otology
125(7): 745746.
[33] El-Tahawy A S. 2010. The prevalence of selected
diseases and syndromes affecting Barki sheep with
special emphasis on their economic impact. Small
Ruminant Research 90: 8387.
[34] Frugere S, Cota L A, Pr`evot F.´et al. 2000.
Immunization of lambs with excretory-secretory
products of Oestrus ovis third-instar larvae and
subsequent experimental challenge. Veterinary
Research 31: 527535.
[35] Gabaj M M, Beesley W N and Awan M A Q. 1993.
Oestrus ovis myiasis in Libyan sheep and goats.
Tropical Animal Health and Production 25(2): 65-
[36] Gebremedhin E Z. 2011. Prevalence of ovine and
caprine oestrosis in Ambo, Ethiopia. Tropical
Animal Health and Production 43(1): 265-270.
[37] Godara R, Sharma R L and Sharma C S. 2010.
Aberrant infestation of goat mandible with Oestrus
ovis larvae. Tropical Animal Health and Production
42: 137-139.
[38] Habela M, Moreno A, Gragera-Slikker A, et al.
2006. Efficacy of eprinomectin pour-on in naturally
Oestrus ovis infested merino sheep in Extremadura,
South-West Spain, Parasitology Research 99: 275.
[39] Hoste H, Lespine A, Lemercier P, et al. 2004.
Efficacy of eprinomectin pour-on against
gastrointestinal nematodes and the nasal bot fly
(Oestrus ovis) in sheep, Veterinary Record 154: 782.
[40] Hoste H, Leveque H and Dorchies Ph. 2001.
Comparison of nematode infections of gastro-
intestinal tract in Angora and dairy goats in a
rangeland environment: relations with the feeding
behaviour. Veterinary Parasitology 101: 127135.
[41] Hoyer P, Williams R R, Lopez M and Cabada M M.
2016. Human nasal myiasis caused by Oestrus
ovis in the highlands of Cusco, Peru: report of a case
and review of the literature. Infectious Diseases
ID 2456735.
[42] Hummelen T, Zeegers J, den Hollander I and ten
Koppel P. 2011. An unusual cause of
sinusitis. Nederlands Tijdschrift voor Geneeskunde.
156(48): A5373.
[43] Ilchmann G, Betke P and Grafe D. 1986. Studies on
oestrosis and its control in the Mongolian People's
Republic. Journal of Veterinary Medicine 41: 128-
[44] Jacquiet P, Trinh Tran T N, Nouvel X, Prevot F,
Grisez C, Hailu T Y, Bergeaud J P, Hoste H,
Dorchies Ph. and Tabouret G. 2005. Regulation of
Oestrus ovis (Diptera: Oestridae) populations in
previously exposed and naïve sheep. Veterinary
Immunology and Immunopathology 105: 95103.
[45] Nguyen Van Khanh N V, Delverdier M, Jacquiet Ph
and Dorchies Ph. 1998. Expression tissulaire de
l’épitope Ki-67 dans le compartiment épithélial de la
International Journal of Medical, Pharmacy and Drug Research (IJMPD) [Vol-2, Issue-4, Jul-Aug, 2018] ISSN: 2456-8015
www.aipublicat Page | 53
muqueuse nasale du mouton et de la chèvre infestésn
naturellement par Oestrus ovis (Linné 1761). Revue
de Médecine Vétérinaire 149(12): 11091113.
[46] Pandey V S. 1989. Epidemiology of Oestrus ovis
infection of sheep in the highveld of Zimbabwe.
Veterinary Parasitology 31(3-4): 275-280.
[47] Paney V S and Ouhelli H. 1984. Epidemiology of
Oestrus ovis infection of sheep in Morocco. Tropical
Animal Health and Production 16: 246 -252.
[48] Papadopoulos E, Chaligiannis I and Morgan E R.
2010. Epidemiology of Oestrus ovis L. (Diptera:
Oestridae) larvae in sheep and goats in Greece.
Small Ruminant Research 89: 5156.
[49] Pathak K M L. 1992. Incidence of Oestrus ovis in
sheep and goats in Rajasthan state of India. Indian
Journal of Animal Science 62, 50.
[50] Roncalli R A. 1984. Efficacy of ivermectin against
Oestrus ovis in sheep. Veterinary and Medicine
Small Animal Medicine and Surgery 29: 1095-1097.
[51] Shcherban N F. 1973. Prevention of Oestrus ovis
infestation in Russia (Trichlorofon Aerosol).
Veterinaria. 2: 7172.
[52] Suarez J L, Scala A, Romero J A, Paz-Silva A,
Pedreira J, Arias M, Diaz P, Morrondo P, Diez-
Banos P and Sanchez-Andrade R. 2005. Analysis of
the humoral immune response to Oestrus ovis in
ovine. Veterinary Parasitology 134: 153158.
[53] Tabouret G, Bret-Bennis L, Dorchies P and Jacquiet
P. 2003a. Serine protease activity in excretory
secretory products of Oestrus ovis (Diptera:
Oestridae) larvae. Veterinary Parasitology 114;
[54] Tabouret G, Lacroux C, Andreoletti O, Bergeaud J
P, Hailu-Tolosa Y, Hoste H, Prevot F, Grisez C,
Dorchies Ph and Jacquiet Ph. 2003b. Cellular and
humoral local immune responses in sheep
experimentally infected with Oestrus ovis (Diptera:
Oestridae). Veterinary Research 34: 231241.
[55] Taylor M A, Coop R L and Wall R L. 2016.
Veterinary Parasitology, 4th Edition. Blackwell
Publishing Ltd, U. K. pp 192-195.
[56] Yilma J M and Dorchies Ph. 1991. Epidemiology of
Oestrus ovis in southwest France, Veterinary
Parasitology 40: 315-323.
[57] Zumpt F. 1965. Myasis in man and animal in the old
world. London Butterworths. pp. 175-179.
Fig.1: Adult O. ovis fly (Anon, 2018)
Fig.2: Third stage larvae of bot fly in nasal sinus
(Anon, 2018)
Fig.3: Cephalopharyngeal skeleton of O. ovis
larvae (Anon, 2018)
Fig.4: Schematic diagram of O. ovis life cycle (Anon,
International Journal of Medical, Pharmacy and Drug Research (IJMPD) [Vol-2, Issue-4, Jul-Aug, 2018] ISSN: 2456-8015
www.aipublicat Page | 54
Fig.5: O. ovis infested sheep (Anon, 2018)
Fig.6: Depression in a sheep due to false gid (Mozaffari
et al., 2013)
Fig.7: snotty nose (Anon, 2018)
... Larvae pass through three stages or instars. 6 The female O. ovis fly is viviparous and deposits L1 in or around the nostrils. Inside the nasal cavities, the first instar larvae attach to the mucous membrane, change to second instars, move up to the sinuses and molt to L3. ...
... 2,5 Oestrus ovis is a problem for sheep and goats worldwide. 6 Both adult and larval stages have an effect on the host. The activities of adult flies during the deposition of larvae cause annoyance, which results in loss of body condition. ...
... Larvae sometimes migrate into the brain of sheep and cause in coordination called "false gid". 4,6 Oestrosis in small ruminants causes substantial economic losses to sheep and goat producers. 6,7 The pathogenic effects cause a reduction in production and serious economic losses, which have been estimated at 1.1-4.6 kg of meat, 200-500 g of wool, and up to 10% of milk per animal. ...
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Background: Ovine oestrosis is an economically important and widely distributed parasitic disease of sheep that is caused by Oestrus ovis larvae across the world. Despite the fact that Oestrus ovis is a common parasite in Ethiopia and that there are many sheep in the study area, there is no information on the prevalence, larval burden, predilection sites, and risk factors associated with Oestrus ovis infestation in sheep in the Dendi district of West Shewa Zone, Ethiopia. Methods: A cross-sectional study was conducted from November 2017 to April 2018, to estimate the prevalence, risk factors, and larval burden, and identify common predilection sites for Oestrus ovis larvae. A total of 180 sheep heads were randomly selected from five purposely selected restaurants in Ginchi town, Dendi district, transported to the laboratory, opened with a hand saw, and visually examined for infestations. The larvae were collected from positive sheep heads and counted. The sites where the larvae were obtained were recorded. The data were analyzed using SPSS version 20 software. Results: Of the total of 180 examined sheep heads, 104 (57.8%) were infested with larvae of Oestrus ovis. In the study, a statistically significant difference (p > 0.05) was not observed in the prevalence of Oestrus ovis in relation to all considered risk factors such as sex, age, and origin of sheep. From 104 infested sheep, a total of 664 larvae were detected in different parts of sheep heads. The mean larval intensity per infected animal with Oestrus ovis was 6.38. In this study, the minimum and maximum numbers of larvae recovered were 1 and 26, respectively. The nasal cavity, nasal sinus and frontal sinus were the predilection sites of Oestrus ovis larvae identified in this study. Conclusion: Oestrosis is an important and common parasitic disease of sheep in the study area.
... Afterward, Myiasis abscess in the lungs leads to starvation that might cause death (Kamal et al., 2021a,b). Occasionally, larvae move from frontal sinuses and nasal cavity to the brain leading to false gid (Patra et al., 2018). Ultimately the pathogenic effects lead to considerably less animal production and significant economic losses to the agricultural industry as estimated roughly as 200-500 gm of wool, 1.1-4.6 kg of meat, and up to 10 % milk per animal (El-Tahawy et al., 2010;Ipek, 2018). ...
Full-text available
The study was planned to evaluate the inter, and intra population genetic variation in general protein banding pattern in Oestrus ovis larvae, by using 10% sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS PAGE). The larvae were collected from slaughtered goats head from five different locations (AAS, PN, LA, GM, and BC) of Karachi, Pakistan. The data obtained was subjected to POPGENE (Population Genetic Analysis) software for analysis. The polymorphic loci within populations ranged from 45.45% to 90.91%. Polymorphic loci observed in all populations were 90.91%. The expected heterozygosity observed was 0.181±0.096 in all populations. The chi-square test showed 5 out of 11 loci at H-W equilibrium. The overall fixation index (FST) value was 0.108, showing that the likelihood of subpopulations being differentiated from one another is about 11 percent. The gene flow value (Nm=2.065) was higher, showing that genes flow occurs between populations. The values of genetic identity were greater, and genetic distance was smaller among all the populations. It means that all the populations were more alike and closer to each other. It was concluded that there was no sympatric and parapatric population differentiation observed among all the population of O. ovis. The populations of the five different locations were not genetically and reproductively isolated from each other.
... Furthermore, this disease can be complicated by sensual tumors and lung abscesses, and sometimes this infection leads to starvation, which might cause death (Dorchies et al., 1993;Özdal et al., 2016). Occasionally, the larvae from frontal sinuses and nasal cavity may move into the brain leading to false gids (Patra et al., 2018). ...
Full-text available
The larvae of Oestrus ovis Linné, 1758 are well-known parasites of goats and sheep. Larval instars of O. ovis are described based on specimens collected from nasal cavities, frontal sinuses and base of the horns of goats from Karachi, Pakistan. Three instars of larvae are described in detail, including body coloration, dorsal and ventral body spines and D-shaped spiracles. Colored illustrations of various larval instars along with typical characters have been given. We also give a key to the third instar larva with some modifications. The mean length (15.65±4.29), width (6.043 ±1.70) and weight (356.3±168.4) of O. ovis larvae were calculated. The one way ANOVA showed significant differences (P<0.05) in length, width and weight of three larval instars of O. ovis. Larvae growth relationship showed negative allometry between weight-length and weight-width, while length-width showed isometry.
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In spring 2016, we analyzed the skull of 44 aoudads (Ammotragus lervia) from Sierra Espuña Regional Park (SE Spain) for the presence of oestrid larvae. Oestrus ovis larvae were found in 27.3% of sampled hosts, with a mean intensity of 1.5 ± 6.1 larvae/per parasitized host (range 1-21). To our knowledge, this is the first report of oestrosis affecting this host species.
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Myiasis is the infestation by dipterous larvae. The larvae can infect intact or decaying tissue including the skin or epithelial surfaces of the orbits, nose, and genitourinary and gastrointestinal tracts. We report a case of primary obligatory nasal myiasis by Oestrus ovis in a 56-year-old man from Cusco in Peru. He presented with nasal pruritus, congestion, and sneezing white “cottony” material. The material was identified as O. ovis larvae. A literature review of publications reporting nasal myiasis caused by O. ovis is presented.
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Larvae of the sheep botfly (Oestrus ovis) normally have sheep or goats as host. In humans the larvae can survive for a short time in the nose or under the eyelids, after which they die or are sneezed out. We describe a 47-year-old woman who during a stay in the Cape Verde Islands developed symptoms of sneezing, a swollen face and an itchy feeling in her nose. These symptoms were due to an infestation of three fully-developed larvae of the O. ovis species in her sinus maxillaries which were later evacuated by endoscopy. In exceptional cases larvae of the O. ovis species can fully mature in a healthy person after a visit to an endemic area. Development into the mature stage has only been described in patients with a poor mucosal immune response.
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Oestrosis is a worldwide myiasis caused by larvae of the fly Oestrus ovis, which are obligate parasites of the nasal and sinus cavities of sheep and goats, especially in Mediterranean countries. The aim of this study was to compare the infection levels and seasonal patterns of oestrosis in sheep and goats from areas of similar climate and to explore some potential risk factors associated with this disease in Greece. Of 450 sheep and goat heads examined, 246 (54%) were infected with O. ovis larvae. Goats (76%, 95% CI 68–82) were more commonly infected than sheep (38%, 95% CI 37–49). Larval stages were recovered during all months of the year from both host species, with an overall mean infection intensity of 8.7±13.1 (mean±SD). Host species, month, area and age, but not nose colour, affected the chance of being infected. Parasite intensity varied but was not affected by these factors except for age and season. Seasonal variation in prevalence was much more pronounced for larval stage 1, than for total larvae. In sheep, infection was generally more common and intense in early spring and in autumn, whereas prevalence peaked in goats in winter. Both prevalence and larval intensity increased with age above 3–4 years in sheep, but not in goats. Patterns of aggregation were consistent with density-dependent constraints to development in the host, and suggested lower susceptibility to larval establishment in goats in spite of higher overall prevalence.
This work explored the prevalence of certain diseases and syndromes affecting adult and young Barki sheep, with an assessment of the consequent economic losses. A surveillance study was conducted by collecting accurate records of 4500 adult Barki sheep and 5580 lambs belonging to 22 farms. The results showed that the overall prevalence of pneumonia, Oestrus ovis infestation, and abscesses in adult sheep was 27%, 24%, and 16%, respectively, and the times of year with the greatest prevalence of each disease were winter, summer, and spring, respectively. With regard to lambs, the overall prevalence of pneumonia and diarrhoea was 18% and 13%, respectively, and both conditions were particularly prevalent during autumn. Pneumonia, O. ovis infestation, and abscesses cost 35 Egyptian pounds (EGP), 40 EGP, and 21 EGP for rams and 19.5 EGP, 19.5 EGP, and 15.6 EGP for ewes, respectively. These disparities in cost were attributable to the differences in weight between the genders. This was also true for lambs; it is interesting to note that pneumonia and diarrhoea cost 25.4 EGP and 13.05 for male lambs and 12 EGP and 2.07 EGP for female lambs.