Pythium insidiosum keratitis: a pictorial essay of natural history

Neufeld, Anastasia; Seamone, Christopher; Maleki, Babak; Heathcote, J. G.

doi:10.1016/j.jcjo.2017.07.002

Cited by 15 publications

(11 citation statements)

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“…An additional 16 pythiosis cases (11 humans and 5 animals; 1-2 cases/country) were from Japan, Israel, Spain, Mexico, Malaysia, South Korea, Jamaica, Haiti, Mali, New Zealand, Taiwan, and an uncertain country (Brazil or Colombia) (Table 1). Among the patients mentioned earlier, five cases were diagnosed with "pythiosis" in their home countries (i.e., France, Spain, and the U.S.A.) after an international trip to Brazil, Colombia, Costa Rica, Israel, Spain, or Thailand (Table 2) [62][63][64][65][66][67]. These patients (who all had ocular pythiosis) were defined as imported cases and then mapped to the known country where they likely acquired the infection (Figure 3).…”

Section: Frequencies and Geographic Distribution Of Pythiosis Casesmentioning

confidence: 99%

Global Distribution and Clinical Features of Pythiosis in Humans and Animals

Yolanda

Krajaejun

2022

JoF

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Pythiosis is a difficult-to-treat infectious disease caused by Pythium insidiosum. The condition is unfamiliar among healthcare workers. Manifestation of pythiosis is similar to other fungal infections, leading to misdiagnosis and delayed treatment. The geographical extent of pythiosis at a global scale is unclear. This study aimed to analyze the clinical information recorded in the scientific literature to comprehensively project epidemiological characteristics, clinical features, and future trends of pythiosis. From 1980 to 2021, 4203 cases of pythiosis in humans (n = 771; 18.3%) and animals (primarily horse, dog, and cow; n = 3432; 81.7%), with an average of 103 cases/year, were recruited. Pythiosis case reports significantly increased in the last decade. Pythiosis spanned 23 tropical, subtropical, and temperate countries worldwide. Some patients acquired pythiosis from a trip to an endemic country. Strikingly, 94.3% of human cases were in India and Thailand, while 79.2% of affected animals were in the U.S.A. and Brazil. Clinical features of pythiosis varied. Vascular and ocular pythiosis were only observed in humans, whereas cutaneous/subcutaneous and gastrointestinal infections were predominant in animals. Mortality depended on host species and clinical forms: for example, none in patients with ocular pythiosis, 0.7% in cows with a cutaneous lesion, 26.8% in humans with vascular disease, 86.4% in dogs with gastrointestinal pathology, and 100% in several animals with disseminated infection. In summary, this study reports up-to-date epidemiological and clinical features of pythiosis in humans and animals. It increases awareness of this life-threatening disease, as the illness or outbreak can exist in any country, not limited to the endemic areas.

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Section: Frequencies and Geographic Distribution Of Pythiosis Casesmentioning

confidence: 99%

Global Distribution and Clinical Features of Pythiosis in Humans and Animals

Yolanda

Krajaejun

2022

JoF

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“…Thus, whether thalassemia is a predisposing factor in ocular pythiosis is not known, warranting the need for additional studies to understand the relationship between ocular pythiosis and thalassemia hemoglobinopathies. Additionally, a fulminant form of Pythium keratitis can be observed in immunocompromised patients (such as those with diabetes or Crohn's disease treated with immunotherapy), which resulted in poor clinical outcomes (i.e., enucleation) (Rathi et al, 2018;Neufeld et al, 2018).…”

Section: Predisposing Factors Host (Intrinsic) Factorsmentioning

confidence: 99%

“…Potential risk factors for pythiosis include farming exposure, direct contact with a water resource (i.e., lake, river, lagoon, swamp, or even swimming pool), and a history of travel to endemic countries, such as Thailand (Krajaejun et al, 2006b;Lelievre et al, 2015;Hasika et al, 2019;Appavu, Prajna & Rajapandian, 2019). Inappropriate hygiene of contact lens can pose a risk (Lekhanont et al, 2009;Lelievre et al, 2015;Badenoch et al, 2001;Maeno et al, 2019;Bernheim et al, 2019;Tanhehco et al, 2011;Barequet, Lavinsky & Rosner, 2013;Neufeld et al, 2018;Raghavan et al, 2018), and exposure to dust or some foreign body in their eyes (Bagga et al, 2018;Hasika et al, 2019) predisposes individuals with no agricultural activity to this infection. The incidence of pythiosis follows a seasonal trend (Hasika et al, 2019;Thanathanee et al, 2013) with outbreaks of Pythium keratitis occurring during the rainy season in Thailand (Thanathanee et al, 2013) and around June to September during monsoon season in South India (Hasika et al, 2019).…”

Section: Environmental (Extrinsic) Factorsmentioning

confidence: 99%

“…To avoid delays in surgery, glycerin-preserved corneal grafts or scleral grafts are alternatives to corneal grafts when corneal donor tissues are not available (Thanathanee et al, 2013). Evisceration or enucleation may be required in cases of extensive lesions involving large area of sclera or endophthalmitis (Lekhanont et al, 2009;Neufeld et al, 2018).…”

Section: Surgical Interventionmentioning

confidence: 99%

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Recent update in diagnosis and treatment of human pythiosis

Chitasombat

Jongkhajornpong

Lekhanont

et al. 2020

PeerJ

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Human pythiosis is an infectious condition with high morbidity and mortality. The causative agent is the oomycete microorganism Pythium insidiosum. The pathogen inhabits ubiquitously in a wet environment, and direct exposure to the pathogen initiates the infection. Most patients with pythiosis require surgical removal of the affected organ, and many patients die from the disease. Awareness of pythiosis among healthcare personnel is increasing. In this review, we summarized and updated information on the diagnosis and treatment of human pythiosis. Vascular and ocular pythiosis are common clinical manifestations. Recognition of the typical clinical features of pythiosis is essential for early diagnosis. The definitive diagnosis of the disease requires laboratory testing, such as microbiological, serological, molecular, and proteomic assays. In vascular pythiosis, surgical intervention to achieve the organism-free margin of the affected tissue, in combination with the use of antifungal drugs and P. insidiosum immunotherapy, remains the recommended treatment. Ocular pythiosis is a serious condition and earliest therapeutic penetrating keratoplasty with wide surgical margin is the mainstay treatment. Thorough clinical assessment is essential in all patients to evaluate the treatment response and detect an early sign of the disease recurrence. In conclusion, early diagnosis and proper management are the keys to an optimal outcome of the patients with pythiosis.

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“…P. insidiosum inhabits freshwater and presents in two forms: mycelium and zoospore [30,31,32]. Clinical manifestations of pythiosis include an infection of artery, eye, skin, or gastrointestinal tract [33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50]. Pythiosis exhibits high morbidity and mortality rates [7,8,28,49,51].…”

Section: Introductionmentioning

confidence: 99%

Review of methods and antimicrobial agents for susceptibility testing against Pythium insidiosum

Yolanda

Krajaejun

2020

Heliyon

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Pythiosis is a life-threatening infectious disease of humans and animals caused by the oomycete microorganism Pythium insidiosum. The disease has been increasingly diagnosed worldwide. P. insidiosum inhabits freshwater and presents in two forms: mycelium and zoospore. Clinical manifestations of pythiosis include an infection of the artery, eye, skin, or gastrointestinal tract. The management of pythiosis is problematic due to the lack of effective treatment. Many patients die from an uncontrolled infection. The drug susceptibility testing provides clinicallyuseful information that could lead to proper drug selection against P. insidiosum. Currently, no standard CLSI protocol for the drug susceptibility of P. insidiosum is available. This review aims at describing methods and antimicrobial agents for susceptibility testing against P. insidiosum. Several in-house in vitro susceptibility methods (i.e., broth microdilution method, radial growth method, and agar diffusion method) have been established for P. insidiosum. Either mycelium or zoospore can be an inoculum. Rabbit is the commonly-used model of pythiosis for in vivo drug susceptibility testing. Based on the susceptibility results (i.e., minimal inhibitory concentration and inhibition zone), several antibacterial and antifungal drugs, alone or combination, exhibited an in vitro or in vivo effect against P. insidiosum. Some distinct compounds, antiseptic agents, essential oils, and plant extracts, also show anti-P. insidiosum activities. Successfully medical treatment, guided by the drug susceptibility data, has been reported in some pythiosis patients. Future studies should emphasize finding a novel and effective anti-P. insidiosum drug, standardizing in vitro susceptibility method and correlating drug susceptibility data and clinical outcome of pythiosis patients for a better interpretation of the susceptibility results.

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Pythium insidiosum keratitis: a pictorial essay of natural history

Cited by 15 publications

References 5 publications

Global Distribution and Clinical Features of Pythiosis in Humans and Animals

Global Distribution and Clinical Features of Pythiosis in Humans and Animals

Recent update in diagnosis and treatment of human pythiosis

Review of methods and antimicrobial agents for susceptibility testing against Pythium insidiosum

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