Introduction
Methods
Wild Bird Cases
Molecular Detection of C. psittaci Infection
Histology and Immunohistochemistry
Results
Wild Bird Cases
Taxonomic group | No. cases tested and results | ||
---|---|---|---|
Positive | Negative | Total | |
Order Passeriformes | |||
Family Paridae | |||
Great tit (Parus major) | 7 | 5 | 12 |
Blue tit (Cyanistes caeruleus) | 3 | 1 | 4 |
Family Prunellidae | |||
Dunnock (Prunella modularis) | 8 | 0 | 8 |
Family Turdidae | |||
Robin (Erithacus rubecula) | 1 | 3 | 4 |
Family Corvidae | |||
Rook (Corvus frugilegus) | 0 | 2 | 2 |
Jackdaw (Corvus monedula) | 0 | 2 | 2 |
Family Fringillidae | |||
Chaffinch (Fringilla coelebs) | 0 | 1 | 1 |
Family Troglodytidae | |||
Wren (Troglodytes troglodytes) | 0 | 1 | 1 |
Family Motacillidae | |||
Pied wagtail (Motacilla alba) | 0 | 1 | 1 |
Order Columbiformes | |||
Family Columbidae | |||
Collared dove (Streptopelia decaocto) | 2 | 1 | 3 |
Feral pigeon (Columba livia) | 0 | 2 | 2 |
Total | 21 | 19 | 40 |
Molecular Detection of C. psittaci Infection
Case no. | Species | 23S rtPCR for Chlamydiaceae
b
| 23S ArrayTube Microarrayd
|
C. psittaci ompA rtPCRe
|
C. psittaci genotyping assayf
| ||
---|---|---|---|---|---|---|---|
Ct-value | Result | Ct-value | Result | ||||
1 | Blue tit | 39.6 | Ques | Neg | 38.6 | Ques | Genotype A-6BC |
2 | Dunnock | 17.2 | Pos |
C. psittaci
| 18.0 | Pos | Genotype A-VS1 |
3 | Dunnock | 41.3 | Ques | Neg | 38.6 | Ques | Weak positive |
4 | Dunnock | 18.8 | Pos |
C. psittaci
| 20.4 | Pos | Genotype A-VS1 |
5 | Great tit | 26.3 | Pos |
C. psittaci
| 27.5 | Pos | Genotype A-VS1 |
6 | Great tit | 38.9c
| Ques |
C. psittaci
| 38.8 | Ques | Weak positive |
7 | Great tit | 37.1 | Pos |
C. psittaci
| 38.2 | Ques | Genotype A-VS1 |
8 | Great tit | 26.0 | Pos |
C. psittaci
| 27.0 | Pos | Genotype A-VS1 |
9 | Dunnock | 21.9 | Pos |
C. psittaci
| 22.7 | Pos | Genotype A-VS1 |
10 | Collared dove | 15.2 | Pos |
C. psittaci
| 20.1 | Pos | Genotype E |
11 | Dunnock | 19.8 | Pos |
C. psittaci
| 23.9 | Pos | Genotype A-VS1 |
12 | Dunnock | 15.9 | Pos |
C. psittaci
| 16.9 | Pos | Genotype A-VS1 |
13 | Robin | 40.5c
| Ques | Neg | 29.6 | Pos | Neg |
14 | Blue tit | 43.7c
| Ques |
C. psittaci
| 40.0 | Ques | Neg |
15 | Collared dove | 13.9 | Pos |
C. psittaci
| 17.7 | Pos | Genotype E |
16 | Great tit | 26.5c
| Ques |
C. psittaci
| 30.6 | Pos | Genotype A-6BC |
17 | Dunnock | 14.6 | Pos |
C. psittaci
| 19.2 | Pos | Genotype A-6BC |
18 | Great tit | 25.9c
| Ques |
C. psittaci
| 30.0 | Pos | Genotype A-6BC |
19 | Dunnock | 15.9c
| Ques |
C. psittaci
| 20.9 | Pos | Genotype A-VS1 |
20 | Great tit | 19.0 | Pos |
C. psittaci
| 23.4 | Pos | Genotype A-VS1 |
21 | Blue tit | 34.3 | Pos | Neg | 39.5 | Ques | Genotype A-VS1 |
Six further cases described in a previous studya
| |||||||
Robin | 16.7 | Pos |
C. psittaci
| 18.1 | Pos | Genotype A-VS1 | |
Robin | 15.6 | Pos |
C. psittaci
| 19.9 | Pos | Genotype A-VS1 | |
Dunnock | 19.1 | Pos |
C. psittaci
| 23.2 | Pos | Genotype A-VS1 | |
Robin | 13.0 | Pos |
C. psittaci
| 17.7 | Pos | Genotype A-VS1 | |
Dunnock | 23.8c
| Ques |
C. psittaci
| 27.9 | Pos | Genotype A-VS1 | |
Dunnock | 11.8 | Pos |
C. psittaci
| 16.5 | Pos | Genotype A-VS1 |
Case no. | Species and signalment | Details of mortality incident | Body condition, [bodyweight (g)] and gross findings on post-mortem examination | ||
---|---|---|---|---|---|
Date and location | Species affected: no. birds found dead (no. seen sick) (and total no. affected individuals) | Clinical signs (if sick birds were observed) and/or perceived cause of death (reported by members of the public) | |||
1 | Blue tit Adult | Oct 2005 Wiltshire, England | Blue tit 1 (0) | None reported | Normal (11.1) Suspected hepatomegaly |
2 | Dunnock Adult male | Jan–Feb 2006 East Sussex, England | Dunnock 2 (1) (2 individuals) | One individual was fluffed up prior to death | Emaciated (17.4) Suspected splenomegaly |
3 | Dunnock Adult | Sep 2006–Jan 2007 Staffordshire, England | Dunnock 1 (1) (1 individual) | Dunnock was fluffed up and lethargic prior to death | Thin (17.0) Hepatomegaly. Necrotic ingluvitis |
Greenfinch 6 (some) | Some greenfinches were fluffed up and unable to fly | ||||
Chaffinch 14 (some) | None reported | ||||
House sparrow 2 (0) | None reported | ||||
4 | Dunnock Adult female | Feb 2007 Northamptonshire, England | Dunnock 1 (0) | Suspected window strike | Emaciated (13.4) Suspected splenomegaly |
5 | Great tit Adult female | Apr 2007 Wrexham, Wales | Great tit 1 (0) | None reported | Thin (14.1) Penetrating wound, rib fractures and fibrinous serositis |
6 | Great tit Adult | Sep–Oct 2007 East Sussex, England | Great tit 1 (0) Greenfinch 0 (1) | Great tit was predated by a cat Greenfinch was fluffed up and lethargic | Normal (20.5) Splenomegaly. Pedunculated skin lesions on wing. Puncture wound |
7 | Great tit Adult | Jul–Sep 2007 Surrey, England | Great tit 3 (3) (≥4
individuals) Blue tit 5 (0) | Multiple individuals had skin growths, particularly on face and wing. Two of the dead great tits were euthanized | Normal (17.6) Splenomegaly. Facial skin lesions. Hemorrhage (euthanasia) |
8 | Great tit Adult male | Jul–Oct 2007 East Sussex, England | Great tit 2 (3) (3 individuals) | Two great tits were lethargic and one other was observed to have a skin growth on wing | Normal (16.9) Splenomegaly. Suspected hepatomegaly. Fibrinous serositis. Hemorrhagic, inflamed neck lesion |
Dunnock 1 (1) (1 individual) | Dunnock was fluffed up before death | ||||
9 | Dunnock Adult | From the same mortality incident as Case 8 (see above) | Emaciated (15.9) Hepatomegaly and splenomegaly | ||
10 | Collared dove Adult female | Sep 2008 Essex, England | Collared dove 1 (1) (1 individual) | Found sick following cat predation and later died | Emaciated (108.5) Serositis, air sacculitis and pericarditis. Ingluvitis. Hepatomegaly |
11 | Dunnock Adult male | Nov 2008–Jan 2009 Powys, Wales | Dunnock 2 (2) (2 individuals) Robin 1 (1) (1 individual) | Dunnocks and robin were fluffed up and lethargic before death | Emaciated (15.7) Anorexia |
Greenfinch 0 (1) | None reported | ||||
12 | Dunnock Adult male | Feb 2009 West Sussex, England | Blue tit 1 (0) | Blue tit was a possible window strike | Thin (19.2) Fractures with no associated hemorrhage |
Dunnock 3 (0) | One dunnock was a possible window strike | ||||
Great tit 3 (0) | One great tit had avian pox (confirmed post-mortem) | ||||
Robin 2 (0) | None reported | ||||
Pheasant 1 (0) | None reported | ||||
13 | Robin Nestling | Apr 2009 Surrey, England | Robin 3 (0) | All of a clutch of 3 nestlings found dead | Thin (11.0) Hepatic congestion |
14 | Blue tit Nestling | May 2009 Staffordshire, England | Blue tit 6 (0) | Six of a clutch of 7 nestlings died | Thin (5.3) Suspected hepatomegaly. Anorexia |
15 | Collared dove Juvenile | Jun 2009 Tyne and Wear, England | Collared dove 1 (1) (1 individual) | Fledgling, seen lethargic before death | Emaciated (104) |
Hepatomegaly, splenomegaly and serositis | |||||
16 | Great tit Adult female | Feb 2010 Wiltshire, England | Great tit 1 (1) (1 individual) | Lethargic prior to death, with skin lesion on head | Thin (15.5) Large skin lesion on head. Suspected splenomegaly |
17 | Dunnock Adult male | Mar 2010 Kent, England | Dunnock 1 (1) (1 individual) | Dunnock was fluffed up and lethargic then predated by a cat | Thin (17.0) Wound, fracture and hemorrhage. Splenomegaly and suspected hepatomegaly. Numerous intestinal helminths |
Blue tit 0 (1) | Blue tit was observed to be “sick” | ||||
18 | Great tit Adult female | Feb–Apr 2010 Surrey, England | Great tit 1 (5) (5 individuals)
| Multiple great tits had fleshy skin growths, one died | Thin (13.7) Multiple skin lesions. Suspected splenomegaly. Numerous lice |
19 | Dunnock Adult male | Apr 2010 Hampshire, England | Dunnock 1 (1) (1 individual) | Fluffed up and lethargic, euthanized | Thin (17.0) Wounds, fractures and hemorrhage (euthanasia). Hepatomegaly and suspected splenomegaly |
20 | Great tit Adult female | Oct 2010 Surrey, England | Great tit 1 (0) | Skin lumps, cat predation | Normal (19.0) Multiple skin lesions. Fracture and hemorrhage. Splenomegaly |
21 | Blue tit Adult male | Mar–Apr 2011 Worcestershire, England | Blue tit 6 (≥9) Great tit 0 (≥2) | Sick blue tits and great tits were lethargic and some appeared to have dyspnea. Some appeared to have epiphora and/or blepharitis and/or blepharospasm. At least two sick blue tits were euthanized and some died | Thin (8.16) Pulmonary congestion. Anorexia |
Pathological Examination
Case no. | Species and signalment | Results of microbiological examination and additional tests | Histopathological findings | Immunohistochemical labeling for Chlamydia sp. specific antigens | Diagnoses |
---|---|---|---|---|---|
2 | Dunnock (Adult male) | Liver and small intestine (SI): Escherichia coli 1. Spleen: no growth | Fibrinous to histiocytic hepatitis with fibrinous thrombosis of the hepatic veins. Fibrinonecrotic, focally extensive splenitis. Fibrinous pneumonia. Histiocytic, focal, mild epicarditis. Proventriculus and gizzard: histiocytic serositis. Giemsa-positive granules in Kupffer cells of the liver, with similar material in some dissociated cells (macrophages or autolyzed hepatocytes), possibly representative of Chlamydial inclusions (or conventional bacteria, such as the E. coli 1 isolated from the tissue). Ziehl-Neelsen (ZN) stain negative for acid-fast agents or inclusions | Intense positive immunolabeling in the heart (endo- and epicardium plus interstitial cells) and serosal surface of the trachea. Foci of positive labeling in the meninges, proventriculus and gizzard. Within the lung, spleen and liver, positive labeling in the cytoplasm of macrophage-like cells (possibly Kupffer cells in the liver) | Chlamydiosis; possible additional bacterial infection |
4 | Dunnock (Adult female) | Liver: mixed growth, predominantly E. coli 1. SI: E. coli 1 and Enterococcus sp. | Fibrinous to histiocytic hepatitis, with fibrinous thrombosis of hepatic veins. Fibrinous pneumonia. Marked atrophy of epicardial adipose tissue and pectoral muscle. Giemsa-positive, granular to linear material in Kupffer cells of the liver, possibly representative of Chlamydial inclusions (or conventional bacteria, such as the E. coli 1 isolated from the tissue; interpretation hindered by autolysis). ZN stain negative for acid-fast agents or inclusions | Positive immunolabeling in the heart (interstitium of the left ventricular wall, right ventricular wall cardio-myocytes, and epicardium), liver (macrophages, hepatocytes and white blood cells) and lung | Chlamydiosis; possible coli-septicemia; possible window strike |
5 | Great tit (Adult female) | Liver: confluent mixed growth. E. coli 1, Moellerella wisconsensis & Enterococcus spp.. Lung: mixed growth predominance Serratia fonticola & M. wisconsensis. Coelomic cavity: few colonies E. coli 1, M. wisconsensis & Enterococcus spp. | Fibrinous perihepatitis and striking cellular infiltrate of portal tracts throughout the liver parenchyma (interpretation hindered by autolysis). Multifocal, acute pulmonary edema. Moderate to marked atrophy of epicardial adipose tissue. ZN and Giemsa stain reveal no Chlamydial inclusions | Positive labeling in the heart (mainly associated with blood vessels), liver (hepatocytes and possibly Kupffer cells), kidney (interstitial tissue) and keel | Chlamydiosis; trauma (possible predation); possible additional (bacterial/viral) infection |
8 | Great tit (Adult male) | Lung, skin lesion and coelom: E. coli 1 & Enterococcus spp. | Vascular endothelial hypertrophy within heart and spleen, with intralesional Gram-negative organisms. Fibrinogranulomatous to mixed cellular, locally extensive, epicarditis, with intralesional Gram-negative organisms. Granulomatous to hemorrhagic, extensive dermatitis, possibly associated with an unidentified mite. Fibrinonecrotizing, focal, acute hepatitis. Fibrinonecrotizing splenitis. Mild pectoral muscle atrophy. Gram-Twort stain shows intra-endothelial organisms as Gram-negative coccobacilli or short rods and shows similar organisms in some epicardial macrophages. ZN and Giemsa stains show no evidence of Chlamydial inclusions | Positive labeling in the heart (epicardium and heart base), spleen (white blood cells), lung (parenchyma and white blood cells), liver (cell-associated, probably macrophages), and skin (inflammatory cells) | Chlamydiosis; possible other bacterial infection |
9 | Dunnock (Adult) | Liver: Mixed growth. E. coli 1 and Providencia stuartii. SI and bursa of Fabricus: E. coli 1 | Fibrinonecrotic, marked hepatitis with multifocal probable fibrinous thrombosis and with intralesional bacterial rods. Fibrinonecrotic splenitis. Fibrinous pneumonia with intrahistiocytic bacterial rods. Focal epicarditis. Giemsa stain shows moderate numbers of bacterial rods in blood vessels in all tissues, within pulmonary macrophages and within some of the fibrinous lesions in the liver and spleen. ZN stain negative for acid-fast agents | Positive labeling in the liver (cell-associated and extracellular labeling in sinusoids and blood vessels), spleen (sub-capsule area), heart (interstitial tissue and myocardium), lung (white blood cells and pleura), and trachea (serosal surface) | Chlamydiosis; possible other bacterial infection |
10 | Collared dove (Adult female) | Liver, SI, crop, pericardium and lung: mixed, E. coli 1 and Enterococcus spp.. Crop: also Candida tropicalis & C. albicans 1. Crop tissue negative for Trichomonas sp. on culture and PCR | Severe candidiasis (crop mucosa markedly thickened, containing massive numbers of Candida sp. spores and pseudohyphae) and secondary bacterial infection (consistent with E. coli 1 infection isolated on culture). Marked, necrotic pericarditis. Liver, gizzard and small intestine: serocoelomitis. Scattered cells within the spleen appear to contain large, basophilic, cytoplasmic inclusions (autolysis hinders interpretation) | Positive specific labeling in the liver, spleen, serosal surface of the small intestine and individual cells (presumed macrophages) in the lung | Chlamydiosis; cat predation; candidiasis |
11 | Dunnock (Adult male) | SI content: Campylobacter sp.. Liver and lung: no growth | Granulocytic enteritis associated with luminal and encysted trematode life stages (consistent with schistosomes but autolysis hinders interpretation). Fibrinonecrotic hepatitis. Focal epicarditis. Mild pulmonary edema (probably agonal). Sarcocystosis of the pectoral muscle. Severe atrophy of epicardial adipose tissue. ZN stain shows no acid-fast agents or inclusions. Giemsa stain faintly highlights Sarcocysts in the pectoral muscle and highlights scanty punctate material in the foci of hepatic necrosis (nuclear dust, or less likely, bacteria or Chlamydial inclusions) | Positive labeling in the lung (diffuse, in cells resembling macrophages and within blood vessels), trachea (serosal surface and intramuscular), pectoral muscle, liver (diffuse, and some associated with bile duct epithelium), proventriculus and gizzard (interstitium and mucosa), heart (cell-associated in interstitium, and myocardium), spleen, and intestines (serosal surface and mucosa) | Chlamydiosis; possible other septicemia; parasitic enteritis; sarcocystosis (probably incidental); intestinal Campylobacter sp. infection (probably incidental) |
15 | Collared dove (Juvenile) | Liver: moderate pure growth E. coli 1. SI: confluent nearly pure E. coli 1. Crop: Trichomonas sp. isolated in Bushby’s medium (subclinical infection). Circovirus-specific PCR on necrotic coelomic tissue negativea
| Fibrinogranulomatous, extensive serositis with intralesional Gram-negative bacteria and some plant material (possible artefactual transfer, or alimentary tract rupture). Fibrinonecrotic splenitis with intralesional Gram-negative bacteria. Diffuse, marked atrophy of adipose tissue. Giemsa stain highlights bacteria in the coelomic exudate but shows no inclusions. A Periodic Acid-Schiff (PAS) preparation highlights plant matter in the exudate on the stomach and intestine but shows no fungal agents. A Gram-Twort highlights the Gram-negative bacteria as coccobacilli to short rods. ZN stain shows no acid-fast agents or inclusions | Positive labeling in the heart (predominantly cell-associated but also extracellular, often perivascular), spleen (capsule and parenchyma), crop (serosal surface), proventriculus and gizzard (serosal surfaces and intramuscular), intestine (within inflammatory cells on the serosal surface), lung (within macrophages in alveoli and interstitium), and kidney (interstitium) | Chlamydiosis; possible other Gram-negative bacterial infection; possible alimentary tract rupture; subclinical Trichomonas sp. infection |
16 | Great tit (Adult female) | Liver: Light nearly pure growth of Serratia ficaria. Small intestine and lung: no growth. Skin lesion: avipox PCR positive | Generalized vascular endothelial hypertrophy in most tissues, with intralesional Gram-negative, PAS-positive organisms. Acute, fibrinous pneumonia with atelectasis. Fibrinonecrotic, extensive hepatitis. Fibrinonecrotic, disseminated, acute or subacute splenitis. Proliferative, multifocally necrotizing, extensive, severe dermatitis with numerous intracytoplasmic inclusion bodies (pathognomonic for avian poxvirus infection) and with minor surface infection by bacterial cocci and mixed fungi. Apparent mild hemoparasitism (compatible with leucocytozoonosis, but other hemoprotozoa could be indistinguishable on histology). ZN and Giemsa stains show no inclusions. Gram-Twort stain shows many of the endothelial bodies as Gram-negative coccoid or short bacillary structures; PAS stain highlights most of the same structures in intense magenta | Positive immunolabeling in the liver (cell-associated, primarily perivascular) and head lesions (inflammatory cells, primarily macrophages). (Brain, trachea, heart, pectoral muscle, lung, esophagus, spleen, proventriculus and gizzard and large intestine devoid of immunolabeling) | Chlamydiosis; avian pox disease with secondary mixed infection; hemoparasitism (significance unclear) |
17 | Dunnock (Adult male) | Liver, SI and peritoneum: pure isolate E.coli 1. | Fibrinonecrotic splenitis with intralesional, coccoid to coccobacillary, Gram-negative bacteria. Pulmonary congestion, edema and atelectasis. Generalized perivascular cellular infiltrates (interpretation hindered by autolysis). Sarcocystosis of the pectoral muscle with no evidence of myositis. ZN and Giemsa stains reveal no Chlamydial inclusions. A Gram-Twort stain shows the splenic bacteria to be Gram-negative, and apparently coccoid to coccobacillary | Positive labeling in the brain (cell-associated and possibly extracellular), trachea (muscle), lung (diffuse, cell-associated and extracellular), heart (diffuse, myocardium), crop (serosa), proventriculus (white blood cells within mucosa and lamina propria), gizzard (mucosa), liver (diffuse, cell-associated and extracellular), spleen (sub-capsular region, associated with white blood cells), large and small intestines, kidney (cell-associated), testis (cell-associated, interstitium), pectoral muscle (myofibrils) | Chlamydiosis; possible other bacterial sepsis; cat predation; heavy intestinal helminth burden; sarcocytosis (presumed incidental infection) |