PROTOTHECOSIS: THE ALGAL DISESASE IN DOMESTIC ANIMAL SPECIES

PROTOTHECOSIS: THE ALGAL DISESASE IN DOMESTIC ANIMAL SPECIES

Dr. ABHISEK MISHRA^1*: M.V.Sc SCHOLAR, DIVISION OF MEDICINE

Dr. VISHNU VADERA¹: M.V.Sc SCHOLAR, DIVISION OF ANIMAL REPRODUCTION

Dr. DIKSHA UPRETI²: M.V.Sc SCHOLAR, DIVISION OF ANIMAL REPRODUCTION

Dr. SHARDHANJALI BEHRA²: B.V.Sc & A.H {FINAL YEAR}

ICAR- INDIAN VETERINARY RESEARCH INSTITUTE, IZATNAGAR, BAREILLY, 243122

^* CORRESPONDIG AUTHOR’S E-MAIL: abhisekmishrabunu1998@gmail.com

ABSTRACT

The genus Prototheca consists of spherical achloric algae cells from the Chlorellaceae family, lacking chloroplasts and photosynthetic ability. Prototheca species are achlorophylls, unicellular algae reproducing asexually in various environments. Prototheca can cause bovine mastitis, with P. zopfii genotype 2 affecting cell viability. In small ruminants and equines, Prototheca can lead to nasal lesions. In pet animals, P. bovis, P. ciferrii, and P. wickerhamii cause protothecosis, often beginning as colitis and progressing to neurological symptoms. P. wickerhamii and P. cutis cause infections in cats, leading to cutaneous nodules and respiratory issues.

KEYWORDS: Prototheca, P. wickerhamii, P. zopfii, P. ciferrii , Mastitis, Algae

INTRODUCTION

The genus Prototheca contains spherical achloric algae cells with a variety of shapes that belong to the Chlorellaceae family. In 1894, German plant physiologist and sugar producer Wilhelm Krüger published a report on Prototheca microorganisms. Despite belonging to the green algae genus, all Prototheca have lost their ability to photosynthesize due to the loss of their chloroplasts due to the absence of photosynthetic capacity and chloroplasts. Some Prototheca are parasitic, while others grow heterotrophically. Similar functional losses in photosynthetic ability have occurred in other groups of photosynthetic organisms, such as apicomplexans, which have transitioned to a parasitic lifestyle. Even though protothecal disease is still rare, more and more cases are being found worldwide, and both human and veterinary medicine are becoming more interested in Prototheca. Infections with Prototheca spp. cause production losses and lower quality of life for affected animals. In this disease, prevention and early detection are critical to preventing the agent from spreading to susceptible hosts. Prototheca species are achlorophylls, unicellular algae. These algae reproduce asexually through endosporulation and are found freely in nature. The mother cell, also known as the sporangium, is an oval or spherical cell that gives rise to two to sixteen daughter cells, or endospores, in these eukaryotic organisms. Prototheca species are found in a variety of environments and favor areas that are moist and contain organic matter.

DISESASES MANIFESTED IN VETERINARY SPECIES

• Bovine mastitis: A variety of pathogens can cause bovine mastitis, but two particularly notable environmental agents are the algae zopfiigenotype 2 (P. bovis) and P. blaschkeae. P. zopfii genotypes 1 and 2 have been shown to vary in their capacity to modify the survival of bovine mammary epithelial cells upon infection, as well as in experimental intramammary infection in mice apoptosis, when bovine mammary cells are infected. Consequently, P. zopfii genotype 1 had no alterations in cell viability, but genotype 2 displayed decreased bovine mammary epithelial cell viability. Early diagnosis is challenging due to the sluggish progression of mastitis caused by Prototheca species, which can be either subclinical or symptomatic. However, the majority of bovine mastitis is persistent and characterised by granulomatous lesions, typically without additional systemic symptoms. In chronic cases, the infection is characterised by the atrophy of the alveoli and the accentuated proliferation of the interstitial connective tissue. The milk may also exhibit mild changes, such as increased somatic cells, decreased milk production, or even a watery secretion appearance with white flakes. Alveolar atrophy, fibroblastic proliferation, infiltration of mononuclear cells, the development of microgranulomas linked to the proliferative process, and limited foci of necrosis persist in chronic instances. Selective isolation and light microscopic demonstration of the organism are typically used to make the diagnosis. These methods can be further supported by fluorescence microscopy, the carbohydrate and alcohol assimilation test, fine needle aspiration linked to electron microscopy, or counter-flow electrophoresis for antibody detection. Conventional antibiotics can only be used when the organism is not sensitive to them. Some degree of benefit was shown by antifungals such as levamisole tetramisole, amphotericin, polymyxin, miconazole, and nystatin.
• Infections in small ruminants & equines: Protothecosis is infrequent in small ruminants. In goats, infections caused by Prototheca spp. are primarily associated with nasal lesions and should be considered in the differential diagnosis of rhinitis. Until now, there have been a few cases reported in sheep. Infections with Prototheca wickerhamiihave been documented in goats in northeastern Brazil. The animals exhibited mucopurulent nasal discharge, restricted airflow, sneezing, proliferative nodules, and laboured and loud breathing. Necrotising lesions of the nasal vestibule, nostrils, and the subcutaneous and dermal tissues of the face and head were among the pathological features.

P.zopfiigeno type 2 infections in horses have been documented in conjunction with other bacteria, specifically Streptococcus equi zooepidemicus and Pithomyces chartarum. The upper respiratory tract is associated with the clinical signs, which include purulent nasal discharge for a few weeks, epistaxis, and nasal mucosal oedema that partially obstructs the nasal meatus. The existence of localised necrotising infection of the maxillary sinus was confirmed by endoscopic investigation. An increased pyogranulomatous rhinitis was seen in the histological analysis, along with defence cell infiltration and a significant amount of algae in the lesion’s vicinity.

• Diseases in pet animals: bovis, P. ciferrii, and P. wickerhamiiall cause protothecosis in dogs. The clinical presentation is more common in the disseminated form than in the localized form. Many cases of canine protothecosis begin as refractory colitis, indicating that the food route appears to be the primary entry point for infectious propagules. The infection tends to spread slowly to other systems, with the only symptoms being digestive-related and lasting for long periods of time before progressing to ocular and/or neurological changes. Interestingly, reports of P. wickerhamii infections have primarily been associated with the development of cutaneous protothecosis. However, it has been noted that P. bovis and P. ciferrii infections are more invasive, involving more tissue and spreading more widely.

P.wickerhamiiand P. cutis have been identified as the species responsible for infections in cats, particularly cutaneous nodules and respiratory syndromes. In the majority of documented cases, a single, localized lesion occurs. In cats, P. wickerhamii caused multifocal lesions that were distal and peripheral, but showed no signs of systemic invasion. Sneezing and coughing were reported in an adult immunocompetent cat with a P. cutis infection.

CONCLUSIONS

Protothecosis is a serious infection caused by Prototheca spp., an alga that infects both humans and animals. Infections with Prototheca spp. result in reduced production and quality of life for the affected animals. Protothecosis has been reported in a variety of domestic and wild animal species, with clinical manifestations including mastitis in cows, respiratory manifestations in goats and cats, and a wide range of clinical signs in dogs. Prototheca spp. infections are difficult to diagnose and treat clinically, so infected animals are frequently discarded or euthanized. Because of the significance of this infection, protothecosis should be considered an important differential diagnosis in routine clinical veterinary medicine.

REFERENCES

1. Ely, V. L., Espindola, J. P., Barasuol, B. M., Sangioni, L. A., Pereira, D. B., & Botton, S. D. A. (2023). Protothecosis in Veterinary Medicine: a minireview. Letters in Applied Microbiology, 76(6)
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5. https://en.wikipedia.org/wiki/Prototheca

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