Veterinaria Italiana, 2012, 48 (1), 99‐107 Histopathology of protozoal infection in animals: a retrospective study at the University of Philippines College of Veterinary Medicine (1972‐2010) Abigail M. Baticados & Waren N. Baticados Summary Istopatologia da infezione The authors describe the first parasitological survey of protozoal infections on tissue slide protozoaria negli animali: uno sections of field cases processed at the studio retrospettivo (1972‐2010) histopathology laboratory of the College of presso l’Università delle Veterinary Medicine (CVM) at the University of the Philippines Los Baños (UPLB). Over 80% Filippine nel College di of the field cases were from Region 4 Medicina Veterinaria (CALABARZON) and the rest were equally distributed from other areas of the Philippines, Riassunto namely: Region 2 (Cagayan Valley), Gli autori descrivono la prima indagine Metropolitan Manila (National Capital Region), parassitologica delle infezioni protozoarie su vetrino Region III (Central Luzon) and Region VI attraverso sezioni di tessuto, di casi trattati in (Western Visayas). Histopathological analyses campo, presso il laboratorio di istopatologia del of tissue sections from 51 archived cases (1972‐ Collegio di Medicina Veterinaria (CVM) attivo 2010) of parasitic aetiology were performed. nell’ Università delle Filippine a Los Baños (UPLB). Microscopic examination of a total of Oltre lʹ80% dei casi provenivano dalla Regione 4 286 histopathological slides revealed the (CALABARZON) e il resto dei casi proveniva presence of several protozoa, including equamente da altre zone delle Filippine, e precisa‐ sarcosporidiosis, hepatic coccidiosis, intestinal mente: dalla Regione 2 (Cagayan Valle), coccidiosis, balantidiosis and leucocyto‐ Metropolitan Manila (National Capital Region), zoonosis. In addition, the finding of Balantidium dalla Regione III (Central Luzon) e dalla Regione and Sarcocystis may have zoonotic implications VI (Western Visayas). Sono state effettuate analisi and can therefore be used as markers of public istopatologiche di sezioni di tessuto provenienti da health importance. 51 casi archiviati (1972‐2010) con eziologia parassitaria. L’ esame microscopico su un totale di Keywords 286 vetrini istopatologici, ha mostrato la presenza di Histopathology, Parasite, Parasitism, Protozoa, alcune malattie protozoarie, tra cui la Sarcocistosi, Philippines, Public health, Tissue section. la Coccidiosi epatica, la Coccidiosi intestinale, la Balantidiasi e la Leucocitozoonosi. Inoltre, la presenza del protozoo Balantidium e Sarcocystis, può avere implicazioni zoonotiche ed essi possono quindi essere usati come importanti indicatori nella salute pubblica. Department of Veterinary Paraclinical Sciences, College of Veterinary Medicine, University of the Philippines Los Baños, Laguna 4031, Philippines [email protected], [email protected] © Istituto G. Caporale 2012 www.izs.it/vet_italiana Vol. 48 (1), Vet Ital 99 Histopathology of protozoal infection in animals: a retrospective study Abigail M. Baticados & Waren N. Baticados at the University of Philippines College of Veterinary Medicine (1972‐2010) Parole chiave Veterinary Medicine (CVM) of the University Istopatologia, Parassita, Parassitismo, Protozoi, of the Philippines Los Baños (UPLB). Another Filippine, Salute pubblica, Sezioni di tessuto. useful method but one which is seldom applied or only performed on a case‐to‐case Introduction basis at the CVM‐UPLB is histopathology of tissue sections. Upon microscopic examination Infections caused by protozoan parasites are of tissues, protozoa may be seen in the widely known to infect various hosts in the intestinal crypts, or free in the lumen of the Philippines and they are responsible for many gastrointestinal tract and in organs of extra‐ diseases observed in both domestic and wild intestinal origin, such as the liver, lungs, animals, as well as in birds and humans. muscle and bile duct, among others (2, 17, 18, Certain species of medical importance have 21, 23, 40). Some examples of protozoa found been investigated with considerable care in the in the blood are Plasmodium spp. (5, 49), country, especially the malarial parasites, the Leukocytozoon spp. (50), Trypanosoma spp. (6, 7, dysentery amoeba, Entamoeba histolytica and 8, 13), those found in faeces are Giardia (22) the dysentery ciliate, Balantidium coli (17). and Balantidium (15); Cryptosporidium spp. (24) According to a previous study that was and species found in extra‐intestinal origins conducted approximately over eight decades are Eimeria grallinida and E. stiedae in the liver ago, several protozoan parasites were found and bile ducts (41); Isospora serine is found in from different animals in the Philippine the respiratory system (12) and Sarcocystis spp. Islands. This includes Eimeria in rabbits, bats which are usually found in the muscles, brain and python, Isospora in the Ruddy kingfisher and in other predilection sites, depending on (Halcyon coromanda) and Crested Myna the species (14, 38). (Acridotheres cristatellus) and Pied Triller or The histopathological examination of tissues Lalage (Lalage nigra) and Haemoproteus in the can be of great value as a diagnostic tool Dollarbird (formerly Broad‐billed Roller) because the finding of the protozoan organism (Eurystomus orientalis), Besra (formerly is definitive. Since suspected protozoal cases Philippine sparrowhawk) (Accipiter virgatus), are not often diagnosed by histopathological Philippine oriole (Oriolus steerii), Philippine examination at the UPLB‐CVM, this study coucal (formerly Java coucal) (Centropus viridis) therefore dealt with a retrospective review of and Spotted Wood‐kingfisher (formerly protozoan infections through histopathological Lindsay’s kingfisher) (Actenoides lindsayi). In examinations. monkeys, several Endamoeba and Trichomonas The paper reports on the different species of species, Endolimax, Dientamoeba, Chilomastix, protozoan parasites found upon histo‐ Giardia lamblia and B. coli were also listed (17). pathological examination. Results of the Generally, there are no specific clinical signs examination revealed an overall percentage of associated with the infection in animals (10, 9.8% positive for protozoa. In addition, the 43), especially protozoan infection in nature. finding of Balantidium (2%) and Sarcocystis Frequently manifested signs include weight (2%) suggests zoonotic implications and may loss, inappetence, weakness and gastro‐ therefore be used as markers of public health intestinal signs, such as diarrhoea. These are importance. often seen in immunocompromised animals, or young animals with heavy infestations (18, 43); Materials and methods however, healthy animals may show various signs as well. Data collection Several methods are used to diagnose the Handwritten records stored in the logbooks of presence of protozoa. Basically, microscopic the Histopathology Laboratory of the examination of blood and faecal samples are Department of Veterinary Paraclinical Sciences the most common methods of examination (DVPS) at the CVM‐UPLB were searched for performed to detect protozoa at the College of keywords ‘parasitism, protozoa or specific 100 Vol. 48 (1), Vet Ital www.izs.it/vet_italiana © Istituto G. Caporale 2012 Abigail M. Baticados & Waren N. Baticados Histopathology of protozoal infection in animals: a retrospective study at the University of Philippines College of Veterinary Medicine (1972‐2010) names of parasitic infections’ from 1972 to Figure 1 shows several stages of the parasite, 2010. The histopathology reports of this cohort specifically macrogametocyte and microga‐ of cases were included as samples for the metocyte, in the liver parenchyma of a rabbit. study. Respective control numbers of the cases In addition, microscopic lesions, such as severe were correlated with the slides and these biliary hyperplasia, were observed. Similarly, sections were set aside for microscopic in Figure 2, partly destroyed intestinal wall examination. with different stages of coccidian parasite were observed. Occupying the intestinal lining were Histopathological examination several macrogametocyte, microgametocyte, The different tissue samples were processed immature oocysts with zygote and schizonts using the routine paraffin technique for with many elongated merozoites. In the case of histological examination. Briefly, tissue Figure 3, sarcocysts or muscle cysts were samples were fixed in 10% formalin solution to displayed. Subsequently, crescent‐shaped arrest tissue decomposition or degeneration. slender bradyzoites were revealed at higher Thereafter, tissues were dehydrated with increasing concentrations of alcohol. A portion of each sample was individually embedded in paraffin and serially sectioned (3 μ ‐10 μ) using American Optical 820 Rotary Microtome® (Scientific Instruments Division, Buffalo, New York), followed by slide mounting and haematoxylin and eosin tissue staining. Processed samples were individually examined under low power and high power magnification and oil immersion objective when necessary. A systematic approach was Figure 1 employed in the examination of the entire Liver of rabbit with Eimeria stiedae infection (A) Grey arrow shows convoluted hyperplastic bile slide. Photomicrographs were obtained using a duct Nikon Eclipse E‐200 microscope with DS‐Fi1‐ Area enclosed a box (bar = 1 mm) (B) Black and white arrows indicate the L2 colour camera head and LCD monitor microgametocyte and microgametocyte, (Nikon, Tokyo). respectively (bar = 1 µm)