Pitiose em animais de produção no Pantanal Matogrossense

Equidae pythiosis in Brazil and the world: a systematic review of the last 63 years (1960-2023)

This systematic review compiles reports of clinical pythiosis in horses, mules and donkeys from 1960 to 2023 worldwide, focusing on Brazil. We searched databases and included 71 articles detailing clinical characteristics, geographic distribution, epidemiology, diagnostic methods, therapies, and outcomes. The results showed that publications on equine pythiosis have significantly increased since 2010. Brazil reported the highest incidence, comprising 55% of cases, predominantly in the southern, northeastern, and central-western regions during summer and autumn. Cutaneous pythiosis was the most prevalent form, generally presenting as single lesions in the appendicular region, and affected females more than males. Diagnosis typically involved histopathology, used alone or with other methods. Various treatments have been employed, with surgery, often combined with chemotherapy and immunotherapy, being the most common. Notably, 80.84% of treated animals recovered, highlighting the effectiveness of these therapies in enhancing survival rates. The limitations of the study included the lack of data in published case reports, which made it difficult to collect and calculate epidemiological data. Additionally, we recognize that pythiosis in Brazil is underreported, since this disease does not have mandatory notification and several cases are not registered and/or reported in the literature. Lastly, it is hypothesized that equid pythiosis may be more widespread than currently known, and its real occurrence in Brazil remains uncertain.

Successful potassium iodide treatment for rhinofacial pythiosis in sheep

BACKGROUND

Pythiosis in sheep is an important disease in Brazil, which could cause rhinitis, dermatitis and alimentary tract inflammation. It is caused by the aquatic oomycete, Pythium insidiosum. The rhinofacial pythiosis causes facial deformity and upper respiratory tract clinical signs associated with necroproliferative masses occupying the rostral nasal cavity and hard palate. Little is known regarding the therapy, prophylaxis and pathogenesis of this disease.

METHODOLOGY

During the 6-year study, we examined 13 sheep presenting rhinofacial pythiosis. The diagnosis was performed through biopsy of the rhinofacial lesions followed by histopathology and immunohistochemistry using specific antibodies against P insidiosum, polymerase chain reaction and an indirect enzyme-linked immunosorbent assay.

RESULTS

This study presents the clinical findings of a potassium iodide treatment of rhinofacial pythiosis in sheep. All sheep were treated with 10 ml of 10% potassium iodide solution, administered orally every day during 63-120 (mean 85) days. Among treated sheep, 84.6% demonstrated complete recovery.

CONCLUSION

Potassium iodide therapy may treat rhinofacial pythiosis in sheep.

History and Perspective of Immunotherapy for Pythiosis

The fungus-like microorganism Pythium insidiosum causes pythiosis, a life-threatening infectious disease increasingly reported worldwide. Antimicrobial drugs are ineffective. Radical surgery is an essential treatment. Pythiosis can resume post-surgically. Immunotherapy using P. insidiosum antigens (PIA) has emerged as an alternative treatment. This review aims at providing up-to-date information of the immunotherapeutic PIA, with the focus on its history, preparation, clinical application, outcome, mechanism, and recent advances, in order to promote the proper use and future development of this treatment modality. P. insidiosum crude extract is the primary source of immunotherapeutic antigens. Based on 967 documented human and animal (mainly horses) pythiosis cases, PIA immunotherapy reduced disease morbidity and mortality. Concerning clinical outcomes, 19.4% of PIA-immunized human patients succumbed to vascular pythiosis instead of 41.0% in unimmunized cases. PIA immunotherapy may not provide an advantage in a local P. insidiosum infection of the eye. Both PIA-immunized and unimmunized horses with pythiosis showed a similar survival rate of ~70%; however, demands for surgical intervention were much lesser in the immunized cases (22.8% vs. 75.2%). The proposed PIA action involves switching the non-protective T-helper-2 to protective T-helper-1 mediated immunity. By exploring the available P. insidiosum genome data, synthetic peptides, recombinant proteins, and nucleic acids are potential sources of the immunotherapeutic antigens worth investigating. The PIA therapeutic property needs improvement for a better prognosis of pythiosis patients.

Outbreak of equine pythiosis in a southeastern region of Brazil: Environmental isolation and phylogeny

Pythiosis is a disease caused by the oomycete Pythium insidiosum, mainly reported in equines, dogs and humans and directly transmitted through contaminant zoospores in aquatic environments. We report the first outbreak of equine pythiosis in five equines. Wound samples were submitted for diagnostic testing including mycological culture and nested PCR. Treatment approaches consisted of conventional and alternative therapies. Microbiological analyses were performed using water samples from the riverbanks close to where the animals had grazed. All animals were positive for P. insidiosum cultures, and two animals responded successfully to alternative therapy (ozone therapy). After culture and molecular analysis of environmental samples, the presence of P. insidiosum in one section of the Tietê River was confirmed through a 99% sequence identity. Phylogenetic analyses using the cytochrome oxidase II gene showed that the animal isolates clustered in clade I and the environmental isolates clustered in clade III. Although the environmental and wound isolates belonged to different genetic clades, we concluded that the Tietê River is an important source of infection by P. insidiosum and that research concerning environmental isolation of P. insidiosum from rivers and lakes should be strongly facilitated in Brazil.

Pythiosis in cattle in Northeastern Brazil

ABSTRACT: The epidemiological, clinical and pathological aspects of cutaneous pythiosis occurring in cattle from three farms in the Northeastern of Brazil are described. A biopsy of the lesions of one bovine from each farm was performed. In two cases, the affected cattle had contact with water accumulated in dams during the dry season in the semiarid region. Another case occurred in the coastal tropical region in cattle grazing around irrigation channels. Clinically, lesions were observed mainly on the skin of the thoracic and/or pelvic limbs, characterized by flat and irregular ulcerated areas or nodules of varying sizes, some with fistulous tracts penetrating deep into the subcutaneous tissue. In one case the regional lymph nodes were affected. Histologically, in all cases, pyogranulomatous dermatitis associated with negative hyphae images, in hematoxylin-eosin stained sections, were observed. In sections stained by Grocott methenamine silver, the hyphae measured 2-8μm and had irregular ramifications and rare septations. Immunohistochemistry technique demonstrated strong immunolabeling for Pythium insidiosum. Pythiosis should be included in the differential diagnosis of dermatopathies in cattle in the Northeastern of Brazil.

Protein profile of Brazilian Pythium insidiosum isolates

Pythium insidiosum is an important aquatic Oomycota that causes pythiosis in mammals, especially horses, dogs, and humans; these inhabit marshy environments in tropical and subtropical areas. The aim of this study was to determine the protein profile, as well as identify likely immunodominant proteins, of Brazilian P. insidiosum isolates from southern Brazil, an important equine pythiosis endemic area. P. insidiosum isolates (horses, n = 20 and dogs, n = 02) were analyzed by SDS-PAGE and Western blot techniques. Horse, cattle, dog, and rabbit sera of both diseased and healthy animals were used to identify P. insidiosum proteins. SDS-PAGE protein profile detected antigens of molecular weights ranging from 100 to 20 KDa. Dog isolates revealed a protein profile similar to that of horse isolates. Anti-P. insidiosum antibodies in the sera of the four species could recognize proteins of different molecular weights (∼74 KDa to ∼24 KDa), and proteins ∼50-55 KDa and ∼34 KDa were shown to be immunodominant. Furthermore, ∼74 KDa, ∼60 KDa, ∼30 KDa and ∼24 KDa proteins were poorly recognized by host species antibodies. The Brazilian P. insidiosum isolates analyzed showed a similar protein profile; however, further studies are essential for the identification and characterization of proteins expressed by P. insidiosum, and an evaluation of the immunological profile of hosts susceptible to this Oomycota is necessary.

Cutaneous Pythiosis in calves: An epidemiologic, pathologic, serologic and molecular characterization

This study reports the epidemiological, pathological and mycological findings of cutaneous pythiosis in cattle in southern Brazil. 23 calves, that were kept next to a river with extensive marshy regions, presented ulcerated cutaneous lesions in thoracic and pelvic limbs, sometimes extending to the ventral thoracic region. Histopathological examination revealed multifocal pyogranulomas in the superficial and deep dermis. The Grocott-Methenamine silver, immunohistochemistry anti-Pythium insidiosum, ELISA serology and molecular characterization demonstrated the agent P. insidiosum in these cases.

Cutaneous pythiosis in a donkey (Equus asinus) in Brazil

Our study describes the clinical, epidemiologic, pathologic, immunohistochemical, and molecular aspects PCR of a case of cutaneous pythiosis in a donkey (Equus asinus) from Brazil. During a dry period, the animal grazed for 4 months around a pond where the vegetation remained green. Skin lesions were nodular, multifocal, and disseminated, mainly involving the legs, ventral chest, and mammary gland. On cut surface, there were multifocal to coalescent discrete yellow foci, and occasional small cavitations with a few kunkers. Ulcerative nodular pyogranulomatous and eosinophilic dermatitis with folliculitis and furunculosis were observed histologically. Hyphae were observed in sections stained with Gomori methenamine silver. Immunohistochemistry with Pythium insidiosum antibodies yielded strong immunostaining of hyphae. P. insidiosum DNA was extracted from tissues in paraffin blocks by amplification of a fragment of 105 bp, which targets the 5.8S ribosomal gene. After the diagnosis of pythiosis, the larger skin lesions were excised and treated as second intention healing wounds, which were completely healed 30 days after resection. Small skin lesions regressed spontaneously in ~60 days. The granulomatous inflammation and outcome of the disease in this donkey were similar to cases of pythiosis in cattle.

Update on pythiosis immunobiology and immunotherapy

Pythiosis is an invasive, ulcerative, pyogranulomatous disease caused by Pythium insidiosum, a fungus-like oomycete that has been reported to affect humans, horses, dogs, and other mammals mainly in tropical and subtropical areas of the world. The disease is characterized by an eosinophilic granulomatous and a Th2 immune response which in turn helps to protect the fungus from the host cells. Pythiosis can present clinically in subcutaneous, gastrointestinal, and vascular tissues or in a systemically disseminated form depending on the species and site of infection. Changes in iron metabolism and anemia are commonly observed. The diagnosis is accomplished through clinical and pathological features, laboratory characteristics of cultures, serological and molecular tests. Treatment includes radical surgery, antimicrobial drugs, immunotherapy or a combination of these treatments. Immunotherapy is a practical and non-invasive alternative for treating pythiosis which is believed to promote a switch from a Th2 to Th1 immune response, resulting in a favorable clinical response. This therapy has demonstrated cure rates above 70% and 55% in horses and humans but low cure rates in dogs and cats. Despite the curative properties of this type of immunotherapy, the antibodies that are produced do not prevent host reinfection. Thus, development of effective adjuvants and new diagnostic techniques for early disease diagnosis are of utmost importance. The aim of this review was to promote pythiosis awareness and to provide an update about the immunotherapy and immunobiology of this disease.