prevalence of cryptosporidium spp. in domestic companion animals of elderly population in...

REV. BRAS. GERIATRIA E GERONTOLOGIA; 2006; 8(1); 9-20

1 71 71 71 71 7Cryptosporidium SPP. in domestic companion animals of elderly population

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Palavras-chave:Cryptosporidium. Prevalncia.Sade do Idoso. AnimaisDomsticos.

Prevalence of cryptosporidium spp. in domestic companion animalsof elderly population in Terespolis, Rio de Janeiro, Brazil

Prevalncia de cryptosporidium spp. em animais domsticos de companhia dapopulao idosa em Terespolis, Rio de Janeiro, Brasil

Cassia R. A. Pereira1

Aldo P. Ferreira2

Rosalina J. Koifman3

Srgio Koifman3

1 Program in Public Health and Environment, National School of Public Health, Rio de Janeiro, RJ,Brazil

2 Center for the Study of Workers Health and Human Ecology, National School of Public Health.Rua Leopoldo Bulhes, 1480 - 21.041-210, Rio de Janeiro, RJ, Brazil

3 Department of Epidemiology and Quantitative Methods in Health, National School of PublicHealth. Rio de Janeiro, RJ, Brazil

Correspondncia / CorrespondenceAldo Pacheco FerreiraE-mail: [email protected]

AbstractObjective: This study aims to highlight the prevalence of cryptosporidiosis indomestic companion animals. Method: Eligible for study were all elderly (over 60years of age) of both sexes who have dogs and / or cats at home, living in the cityof Terespolis and who attended a vaccination post in the municipality duringthe period of national campaigns vaccination against influenza in 2007 and 2008.Results: It was identified the presence of one or more oocysts in fecal material(positive for Cryptosporidium spp.) in 29.0% (87) of these animals and 28.7% hadabout 2 or more oocysts per field. The prevalence by history of diarrhea amongthe 300 animals examined was 27%, reaching 29.5% in dogs and 24.7% in catsshowed no statistically significant difference between species. Conclusion: Thisfact indicates gaps to be more detailed, since there are few studies that explorethe cryptosporidiosis relationship in the human population with companionanimals. The results show the importance of conducting periodic parasitologicalexamination in dogs with or without diarrhea for the specific treatment and theimplementation of prophylaxis and control methods.

ResumoObjetivo: Este estudo visa a destacar a prevalncia da criptosporidiose em animaisde companhia domstica. Mtodo: Foram elegveis para o estudo todos os idosos(acima de 60 anos de idade) de ambos os sexos que tenham ces e / ou gatos emcasa, vivendo na cidade de Terespolis e que foram a um posto de vacinao nomunicpio durante o perodo das campanhas nacionais de vacinao contra a

Key words: Cryptosporidium.Prevalence. Health of theelderly. Domestic Animal.


18 18 18 18 18 REV. BRAS. GERIATR. GERONTOL., RIO DE JANEIRO, 2011; 14(1):17-25

INTRODUCTION

The cryptosporidiosis is an importantzoonosis responsible for clinical signs of diarrheaand gastroenteritis, associated with abdominalpain in humans and domestic animals caused byopportunistic protozoan of the genusCryptosporidium.1 It is transmitted betweenindividuals through oocysts that are alreadyeliminated in the infectious form, being the maintransmission routes the direct contact (person toperson), oral-fecal or indirectly by ingestion ofcontaminated food or water (cysts and oocysts).2

Its distribution is cosmopolitan and presentsvarious hosts where C. muris was the first speciesdescribed in 1907 by Tyzzer, being itsendogenous development restricted to glands ofthe rodent stomach. C. parvum, also described byTyzzer (1912) occurs mainly in the smallintestine of various mammals, includinghumans.3

The protozoan parasite Cryptosporidium hasemerged as an important water contaminant,responsible for several outbreaks ofcryptosporidiosis, affecting until half of 2001,approximately, 427,000 people worldwide. SeveralCryptosporidium species have been described, butonly C. parvum have been associated withgastrointestinal illnesses.4 The cryptosporidiosiscan be fatal in immunocompromised patients andcan severely debilitate immunocompetentindividuals. Another problem is given by the factthat Cryptosporidium oocysts can survive for severalmonths in the aquatic environment and are alsoresistant to disinfection by chlorine used inconventional water treatment.5

The importance of a study on the occurrenceof Cryptosporidium spp. in the aquatic environmenthas been reinforced by Brazilian regulations inHealth Environmental Surveillance associated toDrinking Water Quality Manual (Act n 518,Ministry of Heath)6 that developed andimplemented regulatory standards forCryptosporidium in drinking water. Currently,monitoring of Cryptosporidium in drinking watersystem that supplies cities between 10,000 and100,000 inhabitants is worldwide recommended.7However, the methods commonly used in thedetermination of oocysts in water are highlyvariable and inefficient, for example, theidentification of false-positive by interferencewith algae and others protozoan species.8

The amount and the quality of water are importantfactors for the establishment of health benefits relatedto the incidence reducing and prevalence of severaldiseases, including diarrheal illness.9 Brazil is one ofthe countries with high incidence of diarrhea, whichdirectly affects the rates of infant mortality and withgreater severity among the elderly.10,11

C. parvum has been recognized worldwide asone of the major contaminants of the watersupply.12 The description of hydric contaminationby oocysts presence, probably due to human andanimal origin, are frequently associated withdiarrhea outbreaks and consequently to highmorbidity and mortality levels, preferablyaffecting immunocompromised and children, butalso immunocompetent and animals.13 Althoughof endemic characteristics, diarrhea can presentcases related to itself (clinical, spatial-temporaldistribution, source of infection) that are able tocharacterize an outbreak.

gripe em 2007 e 2008. Resultados: Em 29,0% dos animais pesquisados detectou-se apresena de oocistos e em 28,7% foram observados 2 ou mais oocistos por campo.A prevalncia de histria de diarreia entre os 300 animais examinados foi de27%, atingindo 29,5% em ces e 24,7% em gatos, no mostrando diferenaestatisticamente significativa entre as espcies. Concluso: Este fato indica lacunasa serem mais aprofundadas, uma vez que so poucos estudos que exploram arelao da criptosporidiose com os animais de companhia na populao humana.Os resultados demonstram a importncia de realizao peridica de examesparasitolgicos em ces com e sem diarreia para tratamento especfico e adoomedidas de controle e profilaxia.



The Cryptosporidium transmission through theenvironment is gaining recognition, especially,after the occurrence of numerous outbreaksassociated with consumption or contact withcontaminated waters.14 Some biological factorsand characteristics of Cryptosporidium facilitatedisease transmission through water.13 There is nospecific therapy to treat the high number ofoocysts excreted by infected individuals, around109 to 1010 oocysts, as well as a wide variety ofhosts that act as reservoirs of infection or promotethe cross-transmission or increase the potentialdissemination of cryptosporidiosis.5,9 The oocystsexcretion may or may not coincide with theperiod of symptomatic disease; there may beuncertainties as to its actual occurrence, by thelack of further information on the incidence inasymptomatic individuals.10,13

The elderly population presents a greatersusceptibility to cryptosporidiosis.15-17 Thenumber of fatal cases by specific enteric pathogenspresent from 10 to 100 times higher in elderlythan in the general population.18,19 Mirzaei20observed that in different age groups of Iranpopulation a prevalence of C. parvum in individualsover 51 years ranged from 25.6% with diarrheaand it was more expressive than in cases of non-diarrhea (3.7%).

Studies detach the role of pets, especially dogsand cats, indicating significant benefits for peopleand for society. They would contribute for thephysical, social and emotional development of thechildren and with well-being of its proprietors,particularly the elderly.16 However, companionanimals can be an important source of infectionfor humans, determining diseases genericallyknown as zoonosis, as cryptosporidiosis.16,21Aggravating case related to this infection is givenby the fact that most of the infected animals areasymptomatic.22,23

This still little explored scenario motivated thispaper, that aims to present the prevalence ofcryptosporidiosis in companion animals, in asample of the elderly population from the cityof Terespolis, Rio de Janeiro, Brazil.

METHODS

Local Study

According to the Demographic Census,24Terespolis has a total of 138,081 inhabitants with115,198 (83.5%) inhabitants living in the urbanareas and 22,883 (16.5%) inhabitants living in ruralareas, with a density of 158.7 inhabitant/km2 andurbanization rate of 83.9%.

Population target

All elderly (60 years or older) of both sexeswho have dogs at home and / or cats, living inTerespolis and who hat attended a municipalhealth unit during the national influenzavaccination campaign in 2007 and 2008 wereeligible for the study.

We identified 300 elderly in these twocampaigns who agreed with the term consent forthe anamnesis, carried out through aquestionnaire answered by the researchparticipants, with the aim to gather informationabout residence location and conditions ofhandling the animal in the household.

Were collected fecal samples of companionanimals (dogs and cats). The fecal samplesobtained from the animals were kept in phormolacetic acid 10% and submitted to refrigerationuntil laboratorial analysis.7 Two coprologicalmethods for diagnosis were used. As first methodit was done direct fecal smear, and these stainedby modified Ziehl-Neelsen,25,26 after which it wascarried out the microscopic observation ofsmears. As second method it was weighed twograms of each stool sample which diluted in 15.0ml PBS (Phosphate-buffered saline), filtered andplaced in centrifuge tube. The filtrate wascentrifuged at 750 x g per 7 minutes, discardingthe supernatant. In pellet was added 10.0 ml ofsucrose solution saturated with a specific gravityof 1.2 and centrifuged under the same conditions.Supernatant sample was collected with the aid ofa bacteriological loop being prepared smears ona glass microscopic slide. Drying and fixation



with methanol were followed by staining usingthe modified Ziehl-Neelsen technique. Thestained slides were observed and Cryptosporidiumoocysts were identified by ocular micrometer1000 using a Zeiss Axioskop microscope.

It was considered as relevant for prevalencestudy age data owners grouped by age band (60to 64 years, 65 to 69 years, 70 to 74 years andabove 75 years), sex of owner, number of domesticanimals for household, its distribution accordingto species, its domiciliation inside or outside theresidence, and origin as the location (urban orrural) as well as the diarrhea presence or absencein both species.

Statistical analysis

Descriptive statistics included the calculationfrequency measures and prevalence for diarrhea forinternal and external residence variables, the totalnumber of dogs and cats in residence, presence ofcysts and number of cysts per field observed inthe laboratory, using SPSS software for windowsversion 15.0 (SPSS Inc. Chicago, III., USA).

Ethical issues

The ethical issues were respected according tothe Diretrizes and Normas Regulamentadoras -Resolution # 196/96, through a Free InformedConsent Term and by the consent of theinstitutions Ethical Committee where thisresearch was conducted.

RESULTS

The average age of the 300 elderly, owners ofcompanion animals who participated in thisstudy was 68.9 years with standard deviation (SD)of 6.9 and a median of 68 years, being theminimum age of 58 years and maximum of 90years. The age group 70 years and moreconcentrated 43.3% of participants and there wasa predominance of elderly females (67.7%). Theanimal of choice for company was preferentiallythe dog (71.7%), cats (12.0%) and in 16.3% bothcoexisted. Whether dogs or cats, the majority ofowners (59.3%) had only one pet per householdand 78.3% lived in urban areas (table 1).

Table 1 - Distribution of the elderly population and animals according to predetermined variables,Terespolis, RJ, 2007-2008.

VariablesOwners age Number %

60 to 64 years 102 34.065 to 69 years 68 22.770 to 74 years 64 21.3> 75 years 66 22.0Total 300 100.0

Owners sex Number %Female 203 67.7Male 97 32.3Total 300 100.0

Domestic animal per residence Number %Canine 215 71.7Feline 36 12.0Both 49 16.3

Permanence of the animal inside the residence Number %Yes 172 57.3No 128 42.7

Number of animals per residence Number %1 178 59.32 to 4 103 34.35 or more 19 6.3

Origin of animal residence Number %Urban 235 78.3Rural 65 21.7Total 300 100.0



We identified the presence of one or moreoocysts in fecal material (positivity forCryptosporidium spp.) In 29.0% (87) of these animalsand 28.7% had about 2 to 10 oocysts per field.

Prevalence of diarrhea among the 300 animalsexamined was 27% to 29.5% in dogs and 24.7%in cats, showing no statistically significantdifference between species (table 2).

Tabel 2 - Animal distribution in data on diarrhea, presence of oocysts in laboratory tests and numberof oocysts per field, Terespolis, RJ, 2007-2008.

VariablesDiarrhea in total examined animals Number %

Yes 81 27.0No 219 73.0

Diarrhea in canines Number %Yes 78 29.5No 186 70.5

Diarrhea in felines Number %Yes 64 75.3No 21 24.7

Cryptosporidium spp. oocysts presence Number %Yes 87 29.0No 213 71.0

Number of Cryptosporidium spp. oocysts per field Number %1 62 71.32 16 18.43 5 5.74 or more 4 4.6

The prevalence ratio of diarrhea in the animalsresearched for oocysts presence showed a strongassociation with statistical significance with P-valueof 0.0077 (x2 = 7.09), PR = 5.49 (CI 95%: 3,66-8,21) and when was stratified to oocysts numberper field showed a dose response with increasingeffect measures reaching a PR of 6.39 (CI 95%:3,25-12,56 ) when the oocysts number was 4 ormore per field. It was observed a protective effect

with 27% reduction in the probability of diarrheain animals when they lived inside the home.Considering as reference category (OR = 1) thatonly one companion animal per residence, nosignificant difference was found when comparedwith the prevalence of diarrhea in animals livinguntil a total of 4 per residence (OR = 1.004), butthe probability of diarrheic events was 2.6 timeshigher when living 5 or more animals (table 3).



DISCUSSION

The 300 elderly residents in Terespolis whoattended the national influenza vaccinationcampaign in 2007 and 2008 owned at least onedomestic animal. T population sample studiedwas predominantly female, preferred dogs ascompanion animal and most of them kept theanimals inside the residence.

The study performed in a population of dogsand cats (300) showed a high global prevalence ofpositivity for Cryptosporidium spp. (29.0%), higherthan the one reported among other caninepopulations in the literature. Lallo and Bondan,23in a study conducted with dogs from a universityhospital and two private kennels, reported apositivity rate of 8.85% when the light microscopytechnique was used, and 9.5% with polymerase chain

reaction (PCR) and a similar proportion (10.2%)was observed by Newman and colleagues27 with ananimal population in northwestern Brazil. Aninvestigation conducted with 263 faeces samplescollected from healthy dogs from the city of Lavrasand Viosa, Minas Gerais state, Brazil, found aprevalence of 1.85% for C. parvum.22 Slightly higherproportion was reported by Gennari and colleagues,in So Paulo State,28 analyzed 160 dogs faecessamples with the presence od diarrhea , getting aglobal frequency of 2.83% of excreted oocysts, withno significant difference between the two groups.A study done in Zaragoza, Spain, in 81 dog,registered positivity of 7.4%,29 while El-Ahraf andcolleagues,30 testing 200 dogs in San Bernadino,California, found 2%. Some studies conducted inFinland did not reveal oocysts excretion in adultdogs faeces.31-33. A study conducted in So Paulo,Brazil, showed that oocysts in feces is shedding.23

Tabel 3 - Prevalence ratio of diarrhea in animals for oocysts presence, oocysts number per field,residence type, animals number per residence, Terespolis, RJ, 2007-2008.

Variables Diarrhea

YesN (%)

NoN (%)

TotalN (%)

PR CI (95%)

Oocysts presenceYes 56 (64.37) 31 (35.63) 87 (100) 5.49 3.66 8.21No 25 (11.74) 188 (88.26) 213 (100)

Oocysts number per field1 38 (61,29) 24 (38,71) 62 (100) 5,22 3,43 7,94

2 11 (68,75) 5 (31,25) 16 (100) 5,86 3,57 9,61

3 4 (80) 1 (20) 5 (100) 6,82 3,84 12,10

4 or more 3 (75) 1 (25) 4 (100) 6,39 3,25 12,56

Residence typeInside 39 (22,67) 133 (77,33) 172 (100) 1.00

Outside 42 (32.81) 86 (67.19) 128 (100) 0.73 0.48 1.10

Animals number perresidence

1 43 (24.15) 135 (75.85) 178 (100) 1.002 to 4 26 (25.24) 77 (74.76) 103 (100) 1.04 0,68 1,595 or morte 12 (63.15) 7 (36.85) 19 (100) 2.61 1.69 4.03

2= 7.09; P = 0.0077

PR = Prevalence ratio; CI = Confidence interval; x2 = Chi square; P = P-value



Prevalence of Cryptosporidium spp. in the caninepopulation and those with companion animals(dogs and cats) are sparse and the prevalence ratesreported are very different; some factors may bepointed to justify these differences, especially thedegree of environmental sanitation, the type offecal collection and technical analysis.

The high prevalence of Cryptosporidium inTerespolis region is consistent with the findingsof Pereira and colleagues26, who detected highcontamination (100%) of this protozoan invegetables consumed by the population inTerespolis, a worrying data for water and sludgetreatment, due to non-sanitation actions.

The elderly population, most of the time, ispsychologically dependent on companionanimals, including medical prescription.Infectious diseases are common causes of increasedmorbidity and mortality in elderly patients andshow avery frequent problem in daily geriatricspractice.34 Infections in elderly people are differentfrom the ones presented by the youngpopulation, differences that can be due toimmunological changes or organic malfunction(which decline with age).16

A positive for Cryptosporidium in animals livingwith elderly people aged of 70-74 and 75 or more(43.9%) was very high, setting a higher exposureprobability for this in more susceptiblepopulation groups . A study conducted in Iran 20with 400 individuals the group above 51 yearswho had history of diarrhea had a prevalence of25% in positivity for Cryptosporidium spp.

It can also be noticed that the caninepopulation for one animal per residence comparedto cases of overcrowding (more than 5 animals),showed a lower diarrhea prevalence, probably asa result of minor contact with other animals (oral/ faecal route) avoiding cross-contamination. Itwas also observed that animals that lived insidethe houses had a protective prevalence rate, withreduced probability of presenting diarrhea,

maybe due to the fact that the inner environmentmeans less exposure to Cryptosporidium infection.

Domestic dogs and / or cats are sources ofasymptomatic Cryptosporidium infection, housingthem in their intestinal tract and feeding viableoocysts to the environment through their faeces.22The concern is that the high prevalence ofcryptosporidiosis is only clinically manifested indiarrheal events in cases of weakness of theanimal.23 The prevalence of Cryptosporidium spp.increases with higher population density ofcompanion animals per residence. This factpoints to the need of further deepening of thisresearch, since there are few studies that explorethe cryptosporidiosis relationship between humanpopulation and animals. So it should improve theassessment of the level that this relationshipconforms, that is, elderly companion animals, bythe potential cycle of exposure of the elderly, thusjustifying the attempt to know what happens inthis particular group of population, herepreliminarily studied.

CONCLUSION

Domestic companion animals provide valuableassistance to the physical and mental health oftheir owners. It was found that the closerelationship to these animals, besides benefits, maybring risks to public health, exacerbated by thepotential present of parasites in their animals.Therefore, owners need to be aware of the risksof human infection through faeces of infecteddogs and thus have a greater concern with regularvermifugation of animals (deworming program),in order to provide better health conditions foranimals and avoid the risk of transmission to theowners and for the general population.

We consider relevant the findings of thisresearch, which are important to show thezoonotic relationship of Cryptosporidium spp. in fecalsamples of companion animals of the the elderlypopulationbeing studied.



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Recebido: 30/03/2010Revisado:13/08/2010Aprovado:03/09/2010

prevalence of cryptosporidium spp. in domestic companion animals of elderly population in...

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