Incidence And Risk Factors Of Cryptosporidium Spp. Infection In Water Buffaloes Confined In A Communal Management System In The Philippines
M Villanueva, C Domingo, N Abes, C Mingala
cryptosporidium spp., kinyoun acid fast stain, philippines, water buffalo
M Villanueva, C Domingo, N Abes, C Mingala. Incidence And Risk Factors Of Cryptosporidium Spp. Infection In Water Buffaloes Confined In A Communal Management System In The Philippines. The Internet Journal of Veterinary Medicine. 2009 Volume 8 Number 1.
The study determined the incidence of
Cryptosporidiosis is an emerging zoonotic disease caused by
Philippine carabao and riverine buffalo, like cattle, harbor these zoonotic protozoa,
Cases of cryptosporidial infection among human (Anderson et al., 1982; Cross et al., 2003; Laxer et al., 2003; Capending and Saniel, 2003) as well as in water buffaloes (Fagiolo et al., 2007; Khan, 2000) has been documented on selected urban and rural areas in the Philippines. Knowing that buffalo neonates are reservoir of
The results of cross-transmission experiments, using isolates from farm animals and human patients, suggested by Tzipori et al. (1980) that
Generally, the present study determined the incidence of
Materials and methods
The study utilized a cohort study design where the neonatal calves were followed up starting zero to two weeks old. Thirty-eight (38) newly born calves were enrolled in the study. The dams who delivered them were also enrolled.
Sample and Data Collection
Stool collection of all newly born calves was done in the morning at days 4, 8 and 12 within the two-week observation period. This was based on the two to 10 days incubation period of
Five (5) samples of water contained in five different pails used for drinking by the calves were randomly collected throughout the duration of the study for water analysis using Kinyoun’s stain. Each water sample was collected using a sterile bottle. Water from the pail was agitated first before collecting 30 ml at the center. Thirty (30) milliliters of water from the source was also collected after the first stream of water has been released.
Sample processing and examination
Rare (+) for < 5 oocysts per slide (all fields)
Few to moderate (++) for 1-10 oocysts per ocular field
Numerous (+++) for 11 or more oocysts per ocular field
Analysis of data
Incidence proportion and incidence rate for infected cases were determined according to calf–days:
Incidence proportion of cases = No. of cases
Total no. of calves examined
for the 12 day observation period
Incidence density or rate of cases = No. of cases per calf-days at risk
Point prevalence of
Total no. males examined
Total no. females examined
Percentage distribution of stool consistency by day of observation was computed:
38 stools examined
*stool consistency = solid, mushy, watery
Crude analysis was done to have an idea of the strength and direction of the outcome to the independent variables. Odds ratios and P-values were computed for the association of birth weight of calf, diarrheic dam, and parasitological state of the dam after delivery in relation to cryptosporidiosis.
Results and discussion
Only one female calf with watery stool was found to harbor
Incidence of cryptosporidiosis
There were 38 calves enrolled in the study. Each calf was followed up on day one until day 12. Stool collection was done every four days from day one of birth. Stool consistency and microscopic examination for the presence of
Out of 38 calves, only one became infected on day 8. The incidence proportion is one over 38 or 0.0263 for the 12 day observation period. The average risk of developing cryptosporidiosis during a 12 day period is 2.6% or around 2.6 or three per 100 calves. The incidence rate or density is one per 452 calf-days at risk or 0.00221. The rapidity by which
Distribution of stool consistency based on the time of collection
Results showed that by the end of day 4, 26.31% (10/38) expelled solid formed stool, 63.15% (24/38) mushy stool and 10.5% (4/38), watery stool. At day 8, the percentage of solid stool was reduced to 18.42% while the mushy stool increased to 76.3%. On the other hand, the watery stool decreased to 5.3%. However, on this same day, one infected female calf was detected with oocyst density of (+) or
Description of hypothesized risk factors based on epidemiological measures of association
The point prevalence of
The infected calf in the study had a normal birth weight of 36 kg., which was the ideal weight for a normal buffalo calf. The mean ideal weight is 35.5 kg based on Chi-square Test of association. Birth weight had a computed X2 value of 0.58 with a p-value of 0.445. Therefore, there was no sufficient evidence that birth weight had influence on the
All 38 dams enrolled in the study did not have any history of diarrhea until the time of calving. The infected calf could not have contracted the infection from its mother. Since all calves had the same exposure, result of Chi square test for association was undefined.
Out of the 38 dams enrolled in the study, 10 were found to be infected with oocysts ranging from one to 14 per slide. However, no calf borne from these infected dams developed the infection. The only infected female calf which developed the infection at day 8 after birth came from a non-infected dam. Based on Chi-square Test of association, this risk factor had a computed X2 value of 0.41 with a p-value of 0.52. No sufficient evidence that infected dams at the time of calving had an influence on transmission of the infection to their newly born calves.
There were other incidental findings that could probably explain the incidence of cryptosporidiosis at the farm. First, the 10 infected dams were asymptomatic because all 38 dams did not have history of diarrhea for the past 3 months before parturition. Therefore, cryptosporidiosis among adult animals is not clinically significant to warrant immediate medication. This could explain the lackadaisical attitude of the caretaker in adopting hygienic procedures during calving of dams. Second, two dams calved on the same day wherein one dam that calved earlier was found to be infected while the other dam that bore the calf which later became positive after eight days did not have cryptosporidiosis. Since only one caretaker handled these two dams it could be implied that the caretaker was responsible for mechanically transferring the oocysts to the calf through contaminated hands.
Analysis of water samples from the bucket of selected calf pens were performed by recovering the sediment after centrifugation and staining it with Kinyoun acid fast stain. No water sample was detected with oocysts.
Conclusion and recommendation
Test of association showed no sufficient evidence to conclude that sex, birth weight and parasitologic state of the dam after delivery had an influence over the development of cryptosporidiosis. All dams did not have diarrhea and all calves were exposed to other animals in the pen thus, results of the test of association of these risk factors were undefined. Analysis of water samples from the bucket of selected calf pens and water source using Kinyoun acid fast stain revealed the absence of oocysts.
It is recommended that the duration of cohort study should be lengthened in order to have an epidemiological significance in the incidence of cryptosporidiosis. It is also recommended that other possible risk factors contributing to the transmission of
Furthermore, although the use of Kinyoun acid fast stain procedure has high specificity in detecting
We thank Dr. Libertado C. Cruz, Executive Director of the Philippine Carabao Center, for his valuable support.