DISEASES%20OF%20RESPIRATORY%20SYSTEM

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DISEASES OF RESPIRATORY SYSTEM

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• www.animalmedicinedept.co.nr
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Disease of nasal cavities and sinuses

• Nasal myiasis
• Nasal bot, head bot, head grub

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Definition

• It is a chronic rhinitis and sinusitis of sheep
  characterized by persistent annoyance and
  mucopurulent discharge and is caused by invading
  maggots. This disease presents in all
  sheep-producing countries and maintains high
  incidence in flocks.

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Occurrence

• This disease occurs in all breeds, sexes and ages
  of deep.
• In warm countries both adult and larval phases of
  the disease persist throughout all seasons, but
  in temperate zones, adult flies emerge, mate and
  oviposit only during summer and myiasis continues
  throughout the cold seasons.

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Etiology

• Oestrus ovis is the prevalent fly cause nasal
  myiasis.
• Both the adult insects and their larvae attack
  sheep.

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Pathogenesis

1. Mated female deposit 500 larvae on the nostrils
   of sheep.
2. The first larval stages enter the nasal cavity
   and feed on the mucus and desquamated cells. Then
   first larval stages molt into second larval
   stages.
3. The second larval stages pass into the frontal
   and maxillary sinuses where they grow into third
   stage larvae ?mature larvae?.
4. After 2-10 months, the mature larvae return to
   the nostrils and are sneezed to the exterior.
   They enter the soil and pupate through a period
   of 27 to 36 days.

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Pathogenesis (cont)

1. Adult females deposit larvae throughout the
   summer in temperate zones and throughout most
   seasons in hot zones
2. the movement of numerous maggots in the nasal
   cavities, paranasal sinuses annoy the hosts, and
   animals feeding.
3. In the sinuses, the larvae produce allergic and
   inflammatory reactions. These changes cause
   discomfort and interrupt the animals feeding.
4. Some larvae wander along the trachea into the
   lungs producing fatal reactions.

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Oestrus ovis life cycle
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Larvae within nasal sinus
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Clinical signs

1. Sheep attacked by ovipositing flies stamp with
   their feet, shake their heads, sneeze, and blow
   and ram their noses against the ground or other
   sheep.
2. In some cases, these acts traumatize and infect
   the nostrils.
3. The animals also seek cool areas such damp shade
   where the flies do not frequent.

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Clinical signs (cont)

1. During the time the larvae occupy the nose and
   sinuses, affected sheep may hold their heads
   towards the ground and persistently discharge
   mucopurulent exudate from the nostrils.
2. Breathing may be difficult due to swollen nasal
   membranes and plugged nostrils.
3. The morbidity may reach 80 of a flock, but
   mortality is nil. The course of adult fly attack
   periodically extends through the summer and the
   rhinitis and sinusitis continue up to 10 months.

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Oestrus ovis in nostrils of sheep
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Mucopurelent nasal discharge in sheep bot
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Diagnosis

• Restlessness behavior of sheep during hot-mid
  days and observation of the fly.
• Chronic nasal discharge and finding of larvae in
  sinuses confirm myiasis.

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Treatment

• Important

• Sheep should be treated for nasal myiasis during
  autumn as larvae are small. Killing of mature
  larvae in the sinuses may result in severe
  reaction in the sinus membranes.
• Either of the following compounds and dosage
  rates are highly effective.
• Rafoxinide administered orally at dose rate of
  7.5 mg/kg, B.wt
• Ivermectin at the rate of 50 ug/kg B.wt ?Ivomic,
  Iveen, Ivomax, uvemic, avimic?.

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Pharyngitis

• Definition
• Inflammation of pharyngeal mucosa characterized
  clinically by coughing and painful difficult
  swallowing

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Etiology

1. Pharyngeal trauma usually results from aggressive
   use of equipment used to administer oral
   medication (e.g., balling guns, dose syringes,
   oral speculums, and stomach tubes).
2. Injuries may result in the formation of discrete
   abscesses or extensive and diffuse cellulitis,
   both of which can interfere with swallowing and
   possibly lead to respiratory difficulty or
   distress.
3. Bacteria commonly isolated after an incident of
   pharyngeal trauma include Actinomyces,
   Pasteurella multocida, Pasteurella haemolytica,
   and Fusobacterium.
4. Corynebacterium pseudotuberculosis, the causative
   agent of caseous lymphadenitis in sheep and goats
   may localize in the regional lymph nodes of the
   head, especially the pharyngeal lymph nodes.

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Clinical Signs

• Sheep with pharyngitis have a normal desire to
  eat and drink but may have difficulty swallowing.
• Coughing.
• Respiratory distress in pharyngeal abscess.

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Diagnosis

• Case history
• Clinical signs
• Endoscopic examination

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Treatment

• Antimicrobial antibiotics (oxytetracyclines,
  gentamycin, streptomycin) or sulphonamides.
• Anti-inflammatory corticosteroids such as
  dexamthazone or NSAID such as diclofenac.
• Surgical drainage of abscesses.

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Laryngitis

• Definition
• an inflammation of the mucosa or cartilages of
  the larynx, leading to coughing

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Etiology

• May result from upper respiratory tract infection
• Direct irritation from inhalation of dust, smoke,
  or irritating gas foreign bodies or the trauma
  of intubation, excess vocalization,
• Injury from roping or restraint devices.
• Bacteria Laryngitis may accompany Fusobacterium
  necrophorum or Corynebacterium pyogenes
  infections in sheep.

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Clinical Signs

• A cough is the principal sign of laryngitis when
  edema is slight and the deeper tissues of the
  larynx are not involved. It is harsh, dry, and
  short at first, but becomes soft and moist later
  and may be very painful. It can be induced by
  pressure on the larynx, exposure to cold or dusty
  air, swallowing coarse food or cold water.
• Stridor may result from swelling and reduced
  motion of the arytenoid cartilages.
• Halitosis (bad breath) and difficult, noisy
  breathing may be evident, and the animal may
  stand with its head lowered and mouth open.
• Fever in infectious causes.

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Diagnosis

• Case history
• Clinical signs
• Endoscopic examination (laryngoscope).

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Treatment

1. Corticosteroids should be administered to reduce
   the obstructive effect of the inflammatory
   swellings.
2. Concurrent administration of NSAID (Declofenac 1
   mg/kg BW IV) and systemic antibiotics is also
   necessary.
3. Administration of diuretic drugs, eg, furosemide,
   may be indicated for resolution of laryngeal
   edema if present.

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• Questions