Gastrointestinal Pythiosis in 10 Dogs from California

ArticleinJournal of Veterinary Internal Medicine 22(4):1065-9 · July 2008with35 Reads
Impact Factor: 1.88 · DOI: 10.1111/j.1939-1676.2008.0123.x · Source: PubMed
Abstract

Pythium insidiosum is an aquatic oomycete that causes severe segmental thickening of the canine gastrointestinal (GI) tract, resulting in weight loss, vomiting, diarrhea, and death. Infection in dogs previously has been observed primarily in the southeastern United States. To describe the clinicopathologic and epidemiologic findings associated with GI pythiosis in 10 dogs from California. Dogs were initially identified on the basis of supportive clinical findings and routine histology. Pythiosis was confirmed in each dog with at least one of the following: immunoblot serology, enzyme-linked immunosorbent assay serology, immunohistochemistry, and culture followed by species-specific polymerase chain reaction, rRNA gene sequencing, or both. Between September 2003 and December 2006, GI pythiosis was confirmed in 1 dog from central California and 9 dogs that lived within a 30-mile radius of Davis, CA. Seven of 8 dogs for which environmental data were available had frequent access to flooded rice fields or other water sources. Esophageal lesions were present in 2 of 10 dogs. Common laboratory findings included eosinophilia (7/9), hypoalbuminemia (9/9), and hyperglobulinemia (8/9). Median survival time was 26.5 days (range, 0-122 days), and the disease was ultimately fatal in all 10 dogs. The geographic distribution of pythiosis has widened in recent years to include the western United States. Factors that may have contributed to this change include altered rice-farming practices and landscape irrigation. Veterinarians in California should be familiar with the clinicopathologic features associated with GI pythiosis to aid in early diagnosis and effective treatment.

Full-text

Available from: Stanley Marks, Mar 02, 2016
Brief Communication
Gastrointestinal Pythiosis in 10 Dogs from California
N.A. Berryessa, S.L. Marks, P.A. Pesavento, T. Krasnansky, S.K. Yoshimoto, E.G. Johnson, and
A.M. Grooters
Background: Pythium insidiosum is an aquatic oomycete that causes severe segmental thickening of the canine gastrointes-
tinal (GI) tract, resulting in weight loss, vomiting, diarrhea, and death. Infection in dogs previously has been observed primarily
in the southeastern United States.
Objective: To describe the clinicopathologic and epidemiologic findings associated with GI pythiosis in 10 dogs from
California.
Methods: Dogs were initially identified on the basis of supportive clinical findings and routine histology. Pythiosis was
confirmed in each dog with at least one of the following: immunoblot serology, enzyme-linked immunosorbent assay serology,
immunohistochemistry, and culture followed by species-specific polymerase chain reaction, rRNA gene sequencing, or both.
Results: Between September 2003 and December 2006, GI pythiosis was confirmed in 1 dog from central California and 9
dogs that lived within a 30-mile radius of Davis, CA. Seven of 8 dogs for which environmental data were available had frequent
access to flooded rice fields or other water sources. Esophageal lesions were present in 2 of 10 dogs. Common laboratory find-
ings included eosinophilia (7/9), hypoalbuminemia (9/9), and hyperglobulinemia (8/9). Median survival time was 26.5 days
(range, 0–122 days), and the disease was ultimately fatal in all 10 dogs.
Conclusions and Clinical Importance: The geographic distribution of pythiosis has widened in recent years to include the
western United States. Factors that may have contributed to this change include altered rice-farming practices and landscape
irrigation. Veterinarians in California should be familiar with the clinicopathologic features associated with GI pythiosis to
aid in early diagnosis and effective treatment.
Key words: Canine; Eosinophilia; Fungal; Mycotic; Oomycete; Pythium insidiosum.
P
ythium insidiosum is an aquatic oomycete in the
kingdom Stramenopila, and as such is more closely
related to algae than to fungi. Infections caused by P. in-
sidiosum have been associated with gastrointestinal (GI)
or cutaneous lesions in horses, dogs, cats, cattle, humans,
and several captive exotic species. The worldwide distri-
bution of pythiosis centers on tropical and subtropical
regions, including southeast Asia (Thailand and Indone-
sia), eastern coastal Australia and New Zealand, Brazil,
Costa Rica, and the Caribbean. In the United States,
pythiosis occurs most often in Gulf coast states, but has
also been identified in New Jersey, Virginia, North and
South Carolina, Illinois, Indiana, Kentucky, Tennessee,
Missouri, Oklahoma, and Kansas.
1
Recently, one of the
authors also documented GI pythiosis in a number of
dogs in Arizona.
a
This is surprising given the vast differ-
ence between the arid climate of the southwestern United
States and the tropical climates usually associated with
the disease.
In the fall of 2003, P. insidiosum infection was docu-
mented by the authors in 2 dogs from northern
California. Between May 2004 and December 2006, GI
pythiosis was confirmed in 6 additional dogs living in the
Central Valley of California. Two additional cases were
identified retrospectively. The purpose of this report is to
describe the clinicopathologic and epidemiologic features
associated with GI pythiosis in 10 dogs from California.
Materials and Methods
Eight dogs with signs of GI disease were evaluated at the Uni-
versity of California at Davis Veterinary Medical Teaching Hospital
(UCD-VMTH) or the Country Veterinary Clinic in Live Oak, Cal-
ifornia, between September 2003 and December 2006. Pythiosis was
diagnosed in each of these dogs during the course of their clinical
evaluations. An additional case from the Live Oak clinic previously
thought to be zygomycosis based on routine histology performed at
a reference laboratory in 2003 was retrospectively confirmed to be
pythiosis by immunohistochemical evaluation of archival tissues.
Subsequently, a computerized search of medical and pathology re-
cords at the UCD-VMTH (1997–2007) was conducted to identify
dogs with granulomatous, eosinophilic, or histiocytic GI inflamma-
tion of unknown etiology. The search yielded 1 additional case from
2003 for which paraffin-embedded tissues and a complete medical
record were available. In each dog, the diagnosis was suspected on
the basis of clinical and histologic findings, and confirmed with one
or more of the following: immunoblot serology, enzyme-linked
immunosorbent assay (ELISA) serology, immunohistochemistry,
and culture of the pathogen followed by morphologic as well as mo-
lecular identification by species-specific polymerase chain reaction
(PCR) or rRNA gene sequencing. For the 2 retrospectively identified
cases, the diagnosis was confirmed by immunohistochemistry.
Medical records of the 10 dogs were reviewed to obtain informa-
tion pertaining to signalment, history, physical examination, CBC,
and serum biochemistry. Available radiographic and sonographic
From the Department of Medicine and Epidemiology (Marks), the
Department of Pathology, Microbiology, and Immunology (Pesa-
vento), and the Veterinary Medical Teaching Hospital (Berryessa,
Yoshimoto, Johnson), University of California, School of Veterinary
Medicine, Davis, CA; the Country Veterinary Clinic, Live Oak, CA
(Krasnansky); and the Department of Veterinary Clinical Sciences,
Louisiana State University, Baton Rouge, LA (Grooters). Dr Yoshi-
moto’s present address is VCA West Los Angeles Animal Hospital,
1818 S. Sepulveda Boulevard, Los Angeles, CA. Dr Krasnansky’s
present address is Berryessa Veterinary Clinic, 184 East Grant Street,
Winters, CA.
Corresponding author: Amy M. Grooters, Department of Veteri-
nary Clinical Sciences, Louisiana State University, Baton Rouge, LA
70803-8410; e-mail: agrooters@vetmed.lsu.edu.
Submitted August 19, 2007; Revised November 1, 2007; Ac-
cepted November 17, 2007.
Copyright
r
2008 by the American College of Veterinary Internal
Medicine
10.1111/j.1939-1676.2008.0123.x
J Vet Intern Med 2008;22:1065–1069
Page 1
images were reviewed by a board-certified radiologist (E.G.J.).
Owners were contacted for additional information about travel his-
tory, housing, access to water, and other dogs housed in the same
environment.
For 2 dogs evaluated previously by board-certified veterinary pa-
thologists at a reference laboratory, archival specimens were not
available, but the written report was reviewed. For the remaining 8
dogs, slides stained with hematoxylin and eosin (H&E), Gomori’s
methenamine silver (GMS), Periodic acid Schiff (PAS), Giemsa,
Luna, and immunohistochmemical stains were reviewed by 1 pa-
thologist (P.A.P.). Immunohistochemistry with a polyclonal anti-
Mycobacterium bovis (bacillus Calmette-Gue
´
rin, BCG) antibody
was performed as described previously
2
with the following modifi-
cations: slides were pretreated with 0.4% pepsin in acidulated water
for 30 minutes (rather than 15 minutes) at 37 1C, and were incubated
in primary antibody for 60 minutes (rather than 120 minutes) at
room temperature. Immunohistochemical staining for P. insidiosum
was performed as described previously
b
with an avidin-biotin
immunoperoxidase system
c
with a P. insidiosum-specific polyclonal
antibody raised in chickens. An immunoblot technique previously
utilized for the evaluation of oomycosis in dogs
3
and cats
4
was used
to evaluate anti-P. insidiosum seroreactivity. In addition, seroreac-
tivity was quantitated by a previously described ELISA.
5
Oomycete
isolation and zoosporulation were performed as described previ-
ously.
6,7
The identity of cultured isolates was confirmed by species-
specific PCR or rRNA gene sequencing.
8
Results
The median age at diagnosis was 2 years (range, 0.8–6
years). All dogs were medium or large breed (median
weight, 21 kg; range, 10.6–24.6 kg). Three were spayed
females, 3 were intact females, 2 were neutered males,
and 2 were intact males. Median duration of clinical signs
before veterinary evaluation was 17 days (range, 4–135
days). Presenting complaints included inappetence (7/
10), vomiting or regurgitation (6/10), weight loss (5/10),
and diarrhea (4/10). Physical examination abnormalities
included fever (5/10), thin body condition score (9/10),
and palpable abdominal mass (6/10).
Nine dogs lived within a 30-mile radius of Davis,
California. The 10th lived in central California between
Fresno and Bakersfield. Medical records did not indicate
that any of the dogs had traveled outside the state of
California for 6 months before developing signs of GI
disease, and this was confirmed by phone contact with
owners of 8 dogs (2 had moved and could not be
reached). Three dogs had lived in other states (Arizona,
Colorado, and Washington) previously, but had lived in
California for 4 years, 1 year, and 6 months, respectively,
before developing signs of GI pythiosis. Seven of 8 dogs
for which environmental data were available from own-
ers spent an extensive amount of time outdoors, and 2 of
these were primarily hunting dogs. All 7 dogs had fre-
quent access to water (flooded rice fields for 2, ponds for
2, and a creek, river, and reservoir for 1 dog each). One of
the 8 dogs was kept strictly indoors and had no known
access to bodies of water. All contacted owners reported
having 1 or more dogs housed in the same environment
as the affected dog, and none of these had been observed
to have current or previous signs of GI disease.
At least 1 CBC and 1 serum biochemistry profile were
performed in 9 of the 10 dogs during the course of
disease. Hematologic abnormalities included mild non-
regenerative anemia in 7/9, eosinophilia in 7/9 (median,
1,700/mL; range, 730–5,456/mL; reference interval, 0–
1,200/mL), and mild thrombocytosis in 5/9 (median,
423,000/mL; range, 235,000–610,000/mL; reference interval,
180,000–400,000/mL). Serum biochemistry abnormalities
included hypoalbuminemia in 9/9 (median, 2.6 g/dL;
range, 1.6–2.9 g/dL; reference interval, 3.0–4.4 g/dL),
hyperglobulinemia in 8/9 (median, 4.80 g/dL; range,
3.2–6 g/dL; reference interval, 1.8–3.9 g/dL), and hyper-
calcemia in 1/9 and mild hypocalcemia in 4/9 (median,
9.5 mg/dL; range, 8.1–14.0 mg/dL, reference interval,
9.9–11.4 mg/dL).
Thoracic radiographs were available in 6 dogs, ab-
dominal radiographs in 7 dogs, barium esophagrams in
2 dogs, an upper GI barium study in 1 dog, and abdom-
inal ultrasonography in 3 dogs. In 2/6 dogs, thoracic
radiographs demonstrated a large tubular mediastinal
mass with central luminal gas and ventral deviation of
the trachea and carina. Esophagrams in these 2 dogs
confirmed luminal diameter attenuation and massive an-
nular thickening of the esophagus (Fig 1). Abdominal
radiographic findings included a suspected or definitive
mass lesion in 4/7 and poor abdominal detail in 5/7.
An upper GI study in 1 dog demonstrated a nonobstruc-
tive lesion of the small intestine, typified by marked
focal annular thickening with luminal filling defects.
Abnormal sonographic findings included mesenteric
lymphadenopathy (3/3), abdominal mass (1/3), and ab-
dominal effusion (1/3).
Based on necropsy, surgical, and radiographic find-
ings, lesions were identified in the esophagus in 2 dogs
(Fig 2), stomach in 3 dogs, small intestine in 6 dogs,
and colon in 3 dogs, with multiple lesions in 5 dogs.
Affected regions were segmental, up to 25 cm in length,
and characterized by marked (up to 5 cm) thickening
of the esophageal, gastric, or intestinal wall. Adjacent
omentum and lymph nodes were typically enlarged.
On H&E-stained tissue sections, scattered to coalesc-
ing inflammatory nodules extended from an ulcerated
Fig 1. Esophagram showing an esophageal mass and resultant
stricture in a dog with esophageal pythiosis.
1066 Berryessa et al
Page 2
mucosal surface to circumferentially obliterate the adja-
cent smooth muscle. Inflammatory nodules consisted of
central necrotic debris surrounded closely by fragmented
neutrophils and eosinophils and more peripherally by
large numbers of histiocytes. Necrotizing arteritis was
detected in 4/8 dogs. In all 8 cases for which archival tis-
sue was available, hyphae were visible with GMS and
anti-BCG immunohistochemistry, but failed to stain
with Giemsa, and stained poorly or failed to stain with
PAS. No hyphae were visualized in mesenteric lymph
node sections. The maximal diameter of individual
hyphae ranged from 6 to 15 mm (the larger measurement
for globose hyphal swellings), with infrequent septa and
short branching, often at right angles. In some lesions,
eosinophilic material was visualized around the hyphae
utilizing Luna’s stain.
Serum anti-P. insidiosum ELISA was performed in 7
dogs and was positive in all 7 (median percent positivity,
77%; range, 73–103%; reference interval for infected
dogs, 440%; for healthy dogs, o15%). Immunoblot se-
rology was evaluated in 7 dogs, and in each was positive
for seroreactivity to antigens of P. insidiosum. Immuno-
histochemistry for P. insidiosum was performed on
GMS-positive tissues in 8 dogs, and was positive in 7 of
8. The 1 negative tissue sample was an endoscopic biopsy
specimen from the esophagus in which hyphae were
sparse on GMS-stained sections, and the diagnosis in
this dog was confirmed by serology. Culture of infected
tissues yielded an isolate morphologically consistent with
P. insidiosum in 3/3 dogs in which it was attempted. Am-
plification of mycelial DNA with P. insidiosum-specific
primers was positive in 2 isolates in which it was at-
tempted, and the identity of all 3 cultured isolates was
further confirmed by rRNA gene sequencing.
All dogs were euthanized, or died as a result of their
infection within 4 months of presentation (median sur-
vival, 26.5 days; range, 0–122 days). Treatments included
attempted resection of affected tissue in 5/10, broad-
spectrum antibiotics in 9/10, itraconazole and terbinafine
in 2/10, and corticosteroids in 1/10.
Discussion
The clinicopathologic findings in the dogs described
here are similar to those previously associated with ca-
nine GI pythiosis. Most were young, large-breed dogs
with chronic signs of GI disease, and more than half
had a palpable abdominal mass. Common hematologic
and biochemical findings included anemia, eosinophilia,
hypoalbuminemia, and hyperglobulinemia. The hypo-
calcemia noted in 4 dogs was thought to be due to
hypoalbuminemia, the thrombocytosis in 5 dogs most
likely resulted from systemic inflammation, and the hy-
percalcemia noted in 1 dog has been rarely associated
with GI pythiosis.
9
Lesions most often affected the stom-
ach (3 dogs), small intestine (6 dogs), and colon (3 dogs).
Interestingly, 2 dogs had involvement solely of the esoph-
agus, which has been reported only infrequently.
10
The identification of a relatively large number of cases
over a 3-year period in a small geographic region in
which the infection was previously thought to be absent
raises important questions about the epidemiology of
P. insidiosum infection in California. Although little is
specifically known about the habitat and longevity of
P. insidiosum in the environment, it may be helpful to
view epidemiologic questions in the context of the life
cycle of plant pathogenic oomycetes. The sexual repro-
ductive form produced by pathogenic oomycetes (the
oospore) is a spherical, thick-walled structure designed to
withstand adverse conditions. Oospores may survive in
the soil for long durations (months to years), allowing
the pathogen to persist in the environment between peri-
ods of host availability. In the presence of moisture and
under favorable environmental conditions, the oospore
germinates, forming sporangia from which zoospores are
released, providing a primary inoculum for infection of
host tissues.
11
The zoospore is attracted to and encysts on
susceptible host tissue, forming a thick cell wall and pro-
ducing a germ tube that penetrates the tissue and forms
hyphal structures. Mycelia from infected plant tissue
produce oospores, which are released into the soil or ad-
here to plant roots and debris. For some plant
pathogenic species of Pythium, sporangia may form
directly from mycelia in infected tissue, resulting in
repeated cycles of the asexual phase of the life cycle, con-
sisting of sporangium formation, zoospore release,
zoospore dispersal, and tissue reinfection. Previous in-
vestigators have hypothesized that P. insidiosum uses a
plant substrate to maintain the asexual phase of its life
cycle in aquatic environments, a concept supported by its
ability to infect pieces of water lily and multiple grass
species in the laboratory.
12–14
Frequent exposure to outdoor water sources previ-
ously has been reported as a potential risk factor for
pythiosis.
1,15–17
Of the 8 dogs in this report for whom en-
vironmental information was available, 2 had access to
flooded rice fields, 2 to ponds, 1 to a lake, 1 to a creek,
and 1 to the Sacramento River. Recent environmental
manipulations that may have allowed dogs in northern
California more frequent access to P. insidiosum-infected
water include flooding of rice fields and irrigated land-
scape development. Currently, rice fields cover more
Fig 2. Esophagus. Gross photograph of transverse section. There
is severe, circumferential, mural thickening with subsequent nar-
rowing of the esophageal lumen. The mucosal surface is ulcerated.
1067Pythiosis in California Dogs
Page 3
than 500,000 acres in the north-central California region
in which these cases were identified.
d
The Rice Straw
Burning Reduction Act, an air quality measure enacted
by the California Legislature in 1991, mandated a phase-
down of rice field burning in the Sacramento Valley by
2000. As a result, over the past 10 years, the previously
standard routine of burning rice straw in fields after har-
vest has been largely replaced by flooding rice fields over
the winter, a practice that has been encouraged as an op-
portunity to create a winter habitat for migrating
waterfowl.
18
A similar environmental change resulting
in exposure of animals to floodwater was hypothesized to
be responsible for an increased incidence of cutaneous
pythiosis in North Carolina horses in September 1999,
after Hurricane Floyd.
19
There are several potential mechanisms by which envi-
ronmental changes related to water may contribute to an
increased incidence of pythiosis. First, prolonged or re-
peated moisture exposure in soils that previously
contained relatively small amounts of P. insidiosum could
enhance oospore germination, producing an increased
source of primary inoculum. Second, the introduction of
water to previously dry areas that contain potential plant
substrates for P. insidiosum (such as rice or grass) could
provide an opportunity for increased zoospore produc-
tion via repeated cycles of asexual reproduction through
infection of the plant substrate. Third, field flooding and
landscape irrigation may enhance dispersal of oospores
or zoospores by water movement, increasing the size of
potentially infective areas or contaminating nearby water
sources. Similar examples of plant pathogenic oomycete
dispersion include irrigation water runoff from nursery
or vegetable fields
20,21
and rainwater runoff from north-
ern California forests affected by sudden oak death
caused by Phytophthora ramorum.
22
Finally, the intro-
duction of new water sources near populated areas may
simply increase opportunities for interaction of dogs with
infected water.
In addition to environmental changes involving water,
the appearance of P. insidiosum infection in northern
California may be related to the spread of oospores by
transportation of contaminated soil or plants for land-
scaping or agricultural purposes,
23
or by movement of
people carrying contaminated soil on shoes or bicycle
tires.
22
Nonetheless, factors contributing to the emer-
gence of pythiosis in California are likely to be multiple,
as evidenced by the fact that 1 dog in this case series was
housed strictly indoors.
The successful identification and treatment of P. in-
sidiosum-infected animals in new geographic regions will
require familiarity of veterinary practitioners and pathol-
ogists, with typical clinicopathologic findings, available
confirmatory tests, and treatment options. Pythiosis
should be considered in any young, large-breed dog with
chronic signs of GI disease, a palpable abdominal mass,
or histologic evidence of pyogranulomatous or eosino-
philic gastroenteritis. The diagnosis can be confirmed
by immunoblot or ELISA serology, immunohistochemis-
try, culture, and specific PCR amplification of DNA
extracted from infected tissues.
1
The emergence of pythio-
sis in northern California raises important questions
about the epidemiology of infections caused by patho-
genic oomycetes, and provides an opportunity for future
environmental and epidemiologic studies that may pro-
vide a clearer picture of potential risk factors and a better
understanding of the life cycle of pathogenic oomycetes
that infect mammals.
Acknowledgments
The authors appreciate the technical skills and support
of Diane Nayden in the UC Davis immunohistochemis-
try laboratory, Julie Millard in the LSU histology
laboratory, and Kyle Waite in the LSU Pythium Labo-
ratory.
Footnotes
a
A.M. Grooters, unpublished data
b
Grooters et al. 19th Annual ACVIM Forum, Denver, CO, 2001,
p. 880
c
Avidin-biotin immunoperoxidase system; Vectastain Elite ABC
kit, Vector Laboratories, Burlingame, CA
d
California Rice Commission web page. Available at: http://
www.calrice.org, accessed May 18, 2008
References
1. Grooters AM. Pythiosis, lagenidiosis, and zygomycosis in
small animals. Vet Clin North Am Small Anim Pract 2003;33:695–
720.
2. Bonenberger TE, Ihrke PJ, Naydan DK, et al. Rapid identi-
fication of tissue micro-organisms in skin biopsy specimens from
domestic animals using polyclonal BCG antibody. Vet Dermatol
2001;12:41–47.
3. Grooters AM, Hodgin EC, Bauer RW, et al. Clinicopatho-
logic findings associated with Lagenidium sp. infection in six dogs:
Initial description of an emerging oomycosis. J Vet Intern Med
2003;17:637–646.
4. Rakich PM, Grooters AM, Tang KN. Gastrointestinal
pythiosis in two cats. J Vet Diagn Invest 2005;17:262–269.
5. Grooters AM, Leise BS, Lopez MK, et al. Development and
evaluation of an enzyme-linked immunosorbent assay for the sero-
diagnosis of pythiosis in dogs. J Vet Intern Med 2002;16:142–146.
6. Grooters AM, Whittington A, Lopez MK, et al. Evaluation of
microbial culture techniques for the isolation of Pythium insidiosum
from equine tissues. J Vet Diagn Invest 2002;14:288–294.
7. Mendoza L, Prendas J. A method to obtain rapid zoosporo-
genesis of Pythium insidiosum. Mycopathologia 1988;104:59–62.
8. Grooters AM, Gee MK. Development of a nested PCR assay
for the detection and identification of Pythium insidiosum. J Vet
Intern Med 2002;16:147–152.
9. LeBlanc CJ, Echandi RL, Moore RR, et al. Hypercalcemia
associated with gastric pythiosis in a dog. Vet Clin Pathol 2008;37:
115–120.
10. Patton CS, Hake R, Newton J, et al. Esophagitis due to
Pythium insidiosum infection in two dogs. J Vet Intern Med
1996;10:139–142.
11. Martin FN, Loper JE. Soilborne plant diseases caused by
Pythium spp.: Ecology, epidemiology, and prospects for biological
control. Crit Rev Plant Sci 1999;18:111–181.
1068 Berryessa et al
Page 4
12. Miller RI. Investigations into the biology of three
phycomycotic agents pathogenic for horses in Australia. My-
copathologia 1983;81:23–28.
13. Chaiprasert A, Samerpitak K, Wanachiwanawin W, et al.
Induction of zoospore formation in Thai isolates of Pythium insidio-
sum. Mycoses 1990;33:317–323.
14. Mendoza L, Hernandez F, Ajello L. Life cycle of the human
and animal oomycete pathogen Pythium insidiosum. J Clin Micro-
biol 1993;31:2967–2973.
15. Foil CSO, Short BG, Fadok VA, et al. A report of subcuta-
neous pythiosis in five dogs and a review of the etiologic agent
Pythium spp. J Am Anim Hosp Assoc 1984;20:959–966.
16. Camus AC, Grooters AM, Aguilar RF. Granulomatous
pneumonia caused by Pythium insidiosum in a Central American
jaguar, Panthera onca. J Vet Diagn Invest 2004;16:567–571.
17. Miller RI, Campbell RS. Clinical observations on equine
phycomycosis. Aust Vet J 1982;58:221–226.
18. Elphick CS, Oring LW. Winter management of Californian
rice fields for waterbirds. J Appl Ecol 1998;35:95–108.
19. Vivrette SL, Baker JL, Hudson LC, et al. Dermatitis and
pythiosis in North Carolina horses following Hurricane Floyd. Vet
Dermatol 2000;11(Suppl 1):21.
20. Roberts PD, Urs RR, French-Monar RD, et al. Survival and
recovery of Phytophthora capsici and oomycetes in tailwater and soil
from vegetable fields in Florida. Ann Appl Biol 2005;146:351–359.
21. Hong CX, Moorman GW. Plant pathogens in irrigation
water: Challenges and opportunities. Crit Rev Plant Sci 2005;24:
189–208.
22. Davidson JM, Wickland AC, Patterson HA, et al. Transmis-
sion of Phytophthora ramorum in mixed-evergreen forest in
California. Phytopathology 2005;95:587–596.
23. Ristaino JB, Gumpertz ML. New frontiers in the study of
dispersal and spatial analysis of epidemics caused by species in the
genus Phytophthora. Ann Rev Phytopathol 2000;38:541–576.
1069Pythiosis in California Dogs
Page 5
    • "s the diagnostic efficiency of the molecular-based assay. Alternatively, several investigators have developed immunoperoxidase staining assays (IPS) to facilitate histodiagnosis of pythiosis, using antiserum raised against P. insidiosum antigens. (Brown et. al, 1988; Howerth et. al, 1989; Reis et. al, 2003; Camus et. al, 2004; Rakich et. al, 2005; Berryessa et. al, 2008; White et. al, 2008; Martins et. al, 2012; Pessoa et. al, 2012; Ubiali et. al, 2013). These IPS assays show good detection sensitivity, but some of them have limited detection specificity (Keeratijarut et. al, 2009). Cross reactivity of IPS with some fungi, i.e., Fusarium species, may due to endogenous activity of fungal peroxidase. An "
    [Show abstract] [Hide abstract] ABSTRACT: Pythiosis is an infectious disease of humans and animals living in tropical and subtropical countries. The etiologic agent is the pathogenic oomycete Pythium insidiosum. The disease has a high rate of morbidity and mortality. Patients usually presented with symptoms associated with arterial or ocular infection. Most patients underwent surgical removal of an infected organs (i.e., legs and eyes) to control the infection. Early and accurate diagnosis is important because it leads to prompt treatment and better prognosis for patients with pythiosis. Here, we developed and evaluated an immunofluorescent staining assay (IFA) for histodiagnosis of pythiosis. Rabbit anti-P. insidiosum antibodies were generated for direct detection of P. insidiosum in paraffin-embedded samples. Sixteen P. insidiosum isolates and 16 other fungi were used to prepare paraffin-embedded culture blocks for diagnostic performance evaluation of IFA. As a result, all culture blocks prepared from P. insidiosum were stained positive, while those prepared from the other fungi (control) were stained negative. IFA was further evaluated using paraffin-embedded tissue blocks prepared from infected tissues of patients with vascular pythiosis (n=3) and other fungal infections (2 Candida albicans, 1 Aspergillus flavus, and 1 Fusarium sp). All infected-tissue blocks from pythiosis patients were tested positive, while those from patients with other mycoses were tested negative. Taken together, the developed IFA provided high diagnostic performance (100% sensitivity and specificity), and could be used to facilitate diagnosis of pythiosis.
    Full-text · Conference Paper · Mar 2014
    0Comments 0Citations
    • "Em um caso de zigomicose afetando o trato respiratório em um cão, o diagnóstico foi realizado com base nos achados histopatológicos , histoquímicos e cultura micológica. A zigomicose gastrointestinal em cães e gatos deve ser diferenciada da infecção por P. insidiosum (Grooters 2003, Berryessa et al. 2008). Dentre as micoses que afetaram principalmente a pele destacaram-se a dermatofitose, a malasseziose e a esporotricose . "
    [Show abstract] [Hide abstract] ABSTRACT: Para determinar as principais micoses e oomicoses que acometeram animais domésticos na área de abrangência do Laboratório de Patologia Veterinária (LPV) da Universidade Federal de Santa Maria (UFSM), foi realizado um estudo retrospectivo em 9.487 protocolos de necropsias e 20.199 exames histopatológicos (totalizando 29.686 casos), realizados no LPV-UFSM, entre janeiro de 1990 e dezembro de 2012. Do total de protocolos analisados, 230 apresentaram micoses ou pitiose (oomicose), sendo 179 casos (78%) de micoses e 51 casos (22%) de pitiose. Os protocolos foram revisados para determinar os principais achados referentes à epidemiologia, sinais clínicos e às alterações macroscópicas e microscópicas. Em dois casos (0,8%) não foi possível determinar o gênero ou o grupo do fungo observado. As principais doenças diagnosticadas, em ordem decrescente de prevalência, foram: pitiose, candidíase, aspergilose, zigomicose, dermatofitose, malasseziose, criptococose, megabacteriose e esporotricose. Outras doenças diagnosticadas numa única ocorrência cada foram histoplasmose e pneumocistose. Os equinos foram os mais acometidos pela pitiose e os animais de companhia (cães e gatos) foram os mais acometidos pelas micoses.
    Preview · Article · Mar 2014 · Pesquisa Veterinária Brasileira
    0Comments 3Citations
    • "Canine gastrointestinal pythiosis often occurs along with clinical signs of anorexia, vomiting and weight loss5678910 18]. Additionally, gastrointestinal lesions are characterized by the formation of large masses in the stomach and intestinal walls and may occlude the gastrointestinal lumen56789 18]. All characteristics observed in the present case report are in agreement with the existing literature. "
    [Show abstract] [Hide abstract] ABSTRACT: Pythium insidiosum is an oomycete, a fungal like microorganism, which infects mammals, causing pythiosis in animals and humans, especially in tropical and subtropical regions around the world. The treatment for this infection is very difficult, and therapeutic options commonly comprise surgery, immunotherapy and antimicrobial drugs. The present report describes the clinical healing of a dog with gastrointestinal pythiosis by treatment with a combination of antifungals and immunotherapy, as well as reviews the cases reported in the literature that used some type of therapy for canine pythiosis. A 2.5-year-old male beagle initially showed sporadic vomiting episodes, and this symptom became more frequent 5 months after the onset of clinical signs. Celiotomy procedure found thickness of the stomach wall extending to the pylorus and duodenum. A biopsy was performed, and the diagnosis of pythiosis was made by mycological, histopathological analyses and molecular identification. Therapy was based on an association of terbinafine plus itraconazole during 12 months and immunotherapy for 2.5 months. The healing of the dog reported here allows us to propose the use of immunotherapy associated with antifungal therapy to treat canine gastrointestinal pythiosis. However, additional studies should be performed on a larger number of patients to establish a standard treatment protocol for canine pythiosis.
    Full-text · Article · Aug 2013 · Mycopathologia
    0Comments 2Citations
Show more

Similar publications

Discover cutting-edge research

ResearchGate is where you can find and access the latest publications from your field of research.

Discover more