Diseases of Small Passerine Birds

The following is a brief outline of the diseases of commonly kept Passerine species, their common presentations, how they are transmitted, their treatment and most importantly their prevention.

I. Viral

A. Avian pox
     1. Three forms
          a. Dry (skin)
          b. Diphtheric (wet)
          c. Respiratory (acute)

     2. Mortality 20-100%

     3. Morbidity may be high or low

     4. Transmission via insects, fomites (direct)

     5. Prevention
          a. vaccination
               (1) wing web
               (2) early summer
           b. mosquito control

      6. Diagnosis
          a. presumptive on signs
              (1) Cytology – look for intracytoplasmic inclusion bodies
                   (“Bollinger bodies”)
          b. Histology
     7. Treatment is supportive

B. Paramyxovirus 1 (PMV 1)
     1. Occasionally seen in canaries
     2. Diarrhea / Respiratory signs

C. Paramyxovirus 3 (PMV 3) “Torticollis”
     1. Common disease of “tropical finches”
     2. Morbidity low
     3. Carrier state may exist for several months prior to signs
     4. Diagnosis
          a. presumptive – symptoms
          b. confirmed – serology, virus isolation
     5. Necropsy – not specific
          a. histopathology – pancreatitis
     6. Rule-out – vitamin-E-deficiency

D. Leucosis
     1. Symptoms similar to those of poultry
     2. Viral cause not established

II. Chlamydial

A. Ornithosis
     1. Low morbidity (0-1/4%) / mortality in passerines (10%)
     2. Symptoms nonspecific (Sick Bird Signs “SBS”)
     3. Diagnosis at necropsy
     4. Treatment: Doxycycline in water and / or soft food X 30 days

III. Bacterial

A. Campylobacter infections
     1. Campylobacter fetus subsp.jujuni
     2. Most common in “Tropical finches” (Estrildidae – 40%)
          a. Bengalese (Society) finches commonly asymptomatic carriers
     3. Signs – “SBS” retarded molt, yellow droppings
     4. Necropsy – cachexia, congested GI-tract
     5. Diagnosis – isolation of bacteria
          a. requires special media, micro-aerophilic
     6. Treatment – erythromycin, furoxon, tetracycline, dimetridazol

B.C. Pseudotuberculosis
     1. Yersinia pseudotuberculosis
     2. Most common in winter months
     3. Morbidity high (Europe 12% of necropsies)
     4. Mortality high
     5. Clinical signs not specific “SBS”
     6. Necropsy:
          a. dark, swollen, congested liver/spleen
          b. small focal yellow granulomas
          c. acute catarrhal pneumonia
          d. typhlitis
     7. Diagnosis
          a. presumptive on impression smears of granuloma (gram pos rod)
          b. confirmation on culture
     8. Treatment – Ampicillin, Amoxicillin, Chloramphenicol
     9. Prevention – hygiene

D. Salmonellosis (Paratyphoid)
     1. Salmonella typhimurium
     2. Identical to Pseudotuberculosis clinically and at necropsy
     3. Chronic course most common
     4. “No carrier state” ?
     5. Diagnosis confirmed by culture
     6. Treatment – Trimethoprim +/- sulfa, amoxicillin
     7. Prevention – hygiene

E. Enterobacteriaceae (E.Coli, etc.)
     1. “Sweating disease”
          a. Secondary to underlying problem
               (1) health, hygiene
               (2) Atoxoplasmosis, coccidiosis, psittacosis
          b. More common in finches than canaries
          c. Treatment – neomycin, spectinomycin
               (1) correction of underlying problem
          d. Prevention – hygiene
     2. “Hemorrhagic enteritis” / Hemorrhagic diathesis
          a. Post mortem change
          b. may be associated w/ starvation of small birds

F. Cocci infections
     1. Streptococci and Staphylococci
     2. Signs:
          a. dermatitis, “bumble foot,” conjunctivitis, sinusitis,
              arthritis, pneumonia
     3. Diagnosis
          a. presumptive – gram stains / cytology
          b. confirmation – culture
     4. Treatment – ampicillin, amoxicillin

G. Pseudomonas infection
     1. Pseudomonas spp.
     2. Foul smelling diarrhea, necro-purulent pneumonia
     3. Associated w/ dirty water
          a. sprouted seed
          b. dirty bowls, sipper tubes, water systems
          c. misters, spray bottles, baths
     4. Treatment
          a. appropriate antibiotic
          b. correction of underlying cause
     5. Prevention – hygiene

H. Tuberculosis
     1. Mycobacteria avium
          a. “Classical disease” w/ granuloma in organs uncommon
     2. Two clinical forms
          a. Small granulomas in lung
               (1) often found accidentally on histopathology
          b. Intestinal form w/ bacteria in laminae propria
     3. Very high occurrence in Red hooded siskins, Carduelis cucullatus

I. Other bacterial diseases
     1. Erysipelothrix rhusiopathia, Listeria monocytogenes,
         Pasteurella multocida
     2. Proventriculitis w/ lg.(40×2 micrometers), gram-pos,
        PAS-pos, rod shaped anaerobic bacteria.
          a. birds debilitated (wasted)
          b. increased gastric pH
          c. thick whitish mucous
          d. morbidity high / mortality low
          e. NO KNOWN TREATMENT – supportive care, soft foods, grit

IV. Mycotic infections

A. Candidiasis
     1. Candida spp.
     2. Not significant problem
     3. Associated w/ underlying disease

V. Protozoal infections
(* most important infections of canaries)

A. Atoxoplasma (formerly Lankestrella) “Thick liver disease”
     1. Isospora serini
          a. coccidium w/ a-sexual life cycle in tissue (organs)
              sexual cycle in gut
          b. Young canaries, 2-9 months, European finches
              (Goldfinch, Siskins, Greenfinch, Bullfinch)
     2. Clinical signs
          a. “SBS”, fluffed, quiet, weight loss
          b. “diarrhea”
          c. neurological signs (20%)
          d. death
     3. Post mortem signs / Diagnosis
          a. lg / sometimes spotted liver (focal necrosis)
          b. lg dark spleen
          c. edematous duodenum w/ vascularization
          d. parasites found on impression smears of organs in cytoplasm
             of monocytes. Nucleus of host cell crescent shaped
          e. Coccidia rarely found in feces (shed only 100-200 oocysts/day)
     4. Treatment
          a. Sulphachlor-pyrazin (Esb 3, 30%) in drinking water 5 days
              a week till end of molt
             (1) effects only production of oocysts
     5. Morbidity high (40% of aviaries in Dorrestein study)
     6. Prevention – hygiene

B. Coccidiosis
     1. Isospora canaria
     2. Canaries of all ages older than 2 months
     3. Symptoms – diarrhea, emaciation
     4. Necropsy – edema / hemorrhage of gut wall
     5. Diagnosis – trophozoites on scrapings of duodenum
     6. Treatment – coccidiostatic Rx’s
     7. Prevention – hygiene

C. Cochlosomosis
     1. Cochlosoma sp – flagellate protozoan
     2. Common in Bengalese finches – as asymptomatic carriers
     3. Clinical disease in young Australian finches
          a. 6 weeks to molting
          b. fostered onto Bengalese
     4. Signs – debilitation, “shriveling and staining yellow of the
         fledglings,” difficulty molting, non-digested seed in droppings
     5. Necropsy – Intestine w/ yellow suspension(amylum) and
         non-digested seed.
     6. Diagnosis – based on findings flagellates in fresh, body-warm feces.
     7. Treatment – ronidazol (Ridzol) X 5 days, stop 2 days, repeat
          a. dimetridazol (Emtryl)
               (1) Toxic signs torticollis, stops w/ end of treatment.

D. Toxoplasmosis
     1. Toxoplasma ?
     2. Acute phase – respiratory signs, may be severe
     3. Chronically birds become “blind”
     4. Necropsy
          a. acute – hepato- splenomegaly, catarrhal pneumonia, myositis
               (1) trophozoites easily found on impressions
          b. chronic – iridocyclitis or panophthalmia
               (1) trophozoites difficult to find (from brains)
          c. histopathology – cysts easy to find
     5. Diagnosis
          a. serology, immuno-fluorescence
          b. infection on mice
     6. Treatment – none known

     1. All ages
     2. Clinical signs – respiratory, regurgitation,
         blowing bubbles, emaciation
     3. Diagnosis – parasites present on wet mounts
     4. Necropsy – thickened opaque crop, thick roapy saliva
     5. Treatment – ronidazol, (Ridsol-S, available in Europe)

F. Other protozoal infections
     1. Plasmodium
          a. spread by blood sucking insects

VI. Helminthic parasites

A. Gape worm
     1. Syngamus trachea
     2. not common in passerines

B. Acuaria skrjabini
     1. Mucosal necrosis (ventriculus)
     2. Treatment – levamisole, Fenbendazol.

VII. Arthropods

A. Red mites
     1. Dermanyssus gallinae
     2. Mites spend day in cage, box, nest, etc
     3. Bites bird at night
     4. Mortality – may be high
     5. Symptoms – anemia, respiratory signs, depression
          a. may not find mites!
          b. Treatment – treat bird, environment, remove birds till mites gone

B. White mites
     1. Ornithonyssus sylviarum
     2. Mites spends life on host
     3. Diurnal
     4. Treat w/ ivermectin / dust

C. Scaly face / Tassel foot
     1. Knemidokoptes pilae
     2. Diagnosis on signs, mite in scrapings
     3. Treatment w/ ivermectin

D. Airway mites / Air sac mites
     1. Sternostoma tracheacolum
     2. Signs – cough, wheeze
     3. Australian finches and canaries
     4. Mortality – low
     5. Diagnosis – visualizing mite via transillumination of trachea
     6. Necropsy – +/- airsacculitis, tracheitis, focal pneumonia
          a. may/may not find mites
     7. Treatment – ivermectin

3 thoughts on “Diseases of Small Passerine Birds”

  1. Hello Dr. Jenkins,

    Please excuse me for asking you questions about non-patients. I am concerned about some parakeets (13 presently in one cage) owned by a San Diego friend and kept in a large wooden outdoor cage all year round. The cage has no protection from cold, wind or rain except for a metal sheet on top which overhangs the cage about a half inch. I have told my friend that parakeets should be kept indoors in windy, cold or rainy weather, but she answers that the cage is too large to bring indoors. She has invited me, since I’m concerned, to go over to her house and cover the cage with plastic at night and when the weather is inclement, but I don’t live nearby and don’t think a sheet of plastic is going to keep the birds warm. There are also other parakeets here in a wire cage that juts out from the second floor porch. The only protection from the elements the parakeets in that cage have is a sheet of plastic on one outside corner.

    I consider this abuse. It’s been going on for years and some of the birds die. Are there any local regulations I can point to that protect birds? Is there reading material that I can give this woman that specifies what the birds need to stay healthy?

    I appreciate any time and info you can give me to help these beautiful birds.
    In Gratitude,

  2. Maybe you have some idea and can help. I live on a nature reserve for mainly birds, we have a magpie robin chick which fledged but acted strange, holding its head upside down as if it could not see well and flying in circles. over a few weeks it got better and could fly an land OK. now it has deteriorated back and cannot fly again holdings its head upside down. do you have any help you can give me?

    • Melinda
      I don’t know exactly what diseases might be most common in your area. Chicks with vestibular signs could have had head trauma, or bacterial or viral infections. The most likely infections are viral encephalitis diseases (equine viral encephalitis, West Nile virus to name two) or bacterial infections. There may also me parasites in your area that could cause inner ear and or brain damage (here that might include Toxoplasmosis, Sarcocystis, visceral larval migrans (misplaced intestinal round worms). So, pretty tough to give you an answer. The best treatment is likely good supportive care and try to prevent it from injuring itself.


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