Dynamic modeling of female neutering interventions for free-roaming dog population management in an urban setting of southeastern Iran.

Understanding dynamics of free-roaming dog (FRD) population is critical for planning and implementation of dog population management programs. FRD population size estimation as well as dynamic modeling of dog population under different female dog neutering interventions were investigated in order to determine the most appropriate animal birth control approach. We performed population size estimate of dogs using sight-resight surveys by photography in a randomly selected 25 blocks of the city and all the suburbs of greater Kerman area. Main demographic features were characterized and the dog density distribution was mapped. A dynamic model was developed to predict free-roaming dog population variations after 5 and 10 years. Different scenarios based on 10, 30, 50, 60 and 70% female dog sterilization were considered to predict the effects of animal birth control measures. Free roaming dog population was estimated at 6781 dogs (65.3% males) in Kerman and suburbs with several major population hotspots. Analysis of the dog locations within the city showed that the largest proportion of the dogs were observed in the vacant lots (46.2%). Modeling predictions indicated that, in the absence of management, the free-roaming dog population could increase from a baseline of 6781 to 13,665 dogs (2.02 fold increase) in 5 years and to 19,376 dogs in 10 years (2.86 fold increase). Using a population dynamics model, we simulated five neutering coverages to explore the impact of female neutering on free-roaming dog population size. The 5-year projections of the model have shown that 50% annual female dog sterilization significantly reduced free-roaming dog population by 0.44 comparing to the baseline population. Findings of the present study improve our knowledge on the nature and extent of dog population dynamics in Iran. Effective population control and selection of the most appropriate neutering interventions require a comprehensive knowledge of the characteristics and dynamics of FRD population.

Quantifying the load of Echinococcus granulosus eggs in experimental dog infection using probe-based copro-qPCR analysis.

Designing and implementing Cystic Echinococcosis control programs require quantitative information about the worm load and the intensity of infection in dog populations in endemic areas. So far no "probe-based" molecular quantification tool has been available for E. granulosus. This study was conducted in order to develop and evaluate a qPCR technique for measuring worm load of E. granulosus in the final host. A species-specific TaqMan probe was designed based on the available sequences in GenBank. The study was conducted in two stages. First, stool samples from an experimentally infected dog were collected in days 7, 14, 21, 28, 35 and 49, and were analyzed by real-time qPCR assay. In the second stage, 600 mg negative stool specimens were manually spiked with 1, 5, 10, 20 and 40 eggs and the specimens were analyzed using real-time qPCR. According to the standard curve analysis, 93% efficiency and coefficients of correlation (Rsq) > 0.991 were documented. Quantitative PCR assays showed an increasing signal of infection during the 7-week course of infection. As revealed by the qPCR results from week 5 onward, signals indicative of egg excretion began and reached maximum on week 7. No qPCR signal from the samples containing 1, 10 and 20 eggs was recorded, however the samples containing 5 and 40 eggs produced signals proportional to the primary DNA. The study presents a molecular tool to quantify the burden of E. granulosus infection in dogs. This tool could be applied for measuring the burden of infection in the definitive hosts in surveillance and control programs.

Stool antigen immunodetection for diagnosis of Giardia duodenalis infection in human subjects with HIV and cancer.

Human infection with the protozoan parasite Giardia duodenalis is one the most common parasitic diseases worldwide. Higher incidence rates of giardiasis have been reported from human subjects with multiple debilitating chronic conditions, including hypogammaglobulinemia and common variable immunodeficiency (CVID). In the current study, stool specimens were collected from 199 individuals diagnosed with HIV or cancer and immunocompetent subjects. The sensitivity of microscopy-based detection on fresh stool preparations, trichrome staining and stool antigen immunodetection for the diagnosis of G. duodenalis were 36%, 45.5% and 100%, respectively when compared with a highly sensitive stool-based PCR method as the gold standard. Further multilocus molecular analyses using glutamate dehydrogenase (gdh) and triose phosphate isomerase (tpi) loci demonstrated that the AI genotype of G. duodenalis was the most prevalent, followed by the AII genotype and mixed (AI+B) infections. We concluded that stool antigen immunodetection-based immunoassays and stool-based PCR amplification had comparable sensitivity and specificity for the diagnosis of G. duodenalis infections in these populations. Stool antigen detection-based diagnostic modalities are rapid and accurate and may offer alternatives to conventional microscopy and PCR-based diagnostic methods for the diagnosis of G. duodenalis in human subjects living with HIV or cancer.

Morphometric and Molecular Study of Fasciola Isolates from Ruminants in Iran.

OBJECTIVE: The purpose of the present study was morphometric and molecular characterization of Fasciola isolates from ruminants in Iran. METHODS: Flukes were collected from the livers of 54 naturally infected sheep and cattle. The proportion of body length to width (L/W) of each fresh fluke was measured using a digital caliper. We employed receiver operating characteristic (ROC) curve analysis to explore the reliability of L/W for differentiating the two species. Polymerase chain reaction (PCR)-sequencing was performed on ribosomal Internal Transcribed Spacers (ITS) and mitochondrial cytochrome c oxidase subunit 1 (cox1) genes. The sequences were then analyzed and phylogenetic relationships were investigated. RESULT: Forty-eight out of 54 isolates (88.9%) were identified as F. hepatica and four isolates (7.4%) as F. gigantica. All the sheep isolates were F. hepatica, while 4 out of 10 cattle were infected with F. gigantica. The morphometric study revealed an L/W ratio of 1.2 to 6.5 in Fasciola isolates with significantly higher L/W ratio in F. gigantica (p<0.00). According to the ROC curve analysis, the L/W value of 3.55 was regarded as the critical value to discriminate between the two species. CONCLUSIONS: Findings of the present study indicate the presence of both Fasciola species in southeastern Iran. The phylogenetic analysis revealed two different clades representing F. hepatica and F. gigantica. The two isolates in this study were described as Fasciola sp. The mitochondrial DNA of these isolates were similar to F. hepatica, while their ITS fragments were identical to F. gigantica.

Morphometric Analysis of Larval Rostellar Hooks in Taenia multiceps of Sheep in Iran and Its Association with Mitochondrial Gene Variability.

BACKGROUND: The purposes of the present study were morphometric characterization of rostellar hooks of Taenia multiceps and to investigate the association of hook length variation and the variability within two mitochondrial genes of sheep isolates of the parasite. METHODS: Up to 4500 sheep brains were examined for the presence of C. cerebralis. Biometric characters based on the larval rostellar hook size were measured for each individual isolate. Representative mitochondrial CO1 and 12S rRNA gene sequences for each of the isolates were obtained from NCBI GenBank. Morphometric and genetic data were analyzed using cluster analysis, Interclass Correlation Coefficient (ICC) and random effects model. RESULTS: One hundred and fourteen sheep (2.5%) were found infected with the coenuri. The minimum and maximum number of scoleces per cyst was 40 and 550 respectively. Each scolex contained 22-27 hooks arranged in two rows of large and small hooks. The average total length of the large and small hooks was 158.9 and 112.1 µm, respectively. Using ICC, statistically significant clusters of different hook sizes were identified within the isolates. The length of the large and small hooks was significantly associated with the variability in mitochondrial 12S rRNA gene. CONCLUSION: Taenia multiceps, is a relatively important zoonotic infection in Iranian sheep with the prevalence rate of 2.5%. Hook length analysis revealed statistically significant difference among individual isolates. Associations between the rostellar hook length and variability in the mitochondrial 12S rRNA was documented.