Reservoirs of pathogenic Leptospira species in Uganda

Introduction Leptospira are spirochete bacteria, including pathogenic species that cause leptospirosis, a zoonotic disease endemic in the tropics. In Uganda, Leptospira seroprevalence has been reported among outpatients at three hospitals, with human-animal interaction implicated as source of human Leptospira exposures. However, corresponding animal Leptospira infection has only been demonstrated in cattle, leaving the status in several potential reservoirs like other livestock species and environmental sources unknown. The current study aims at determining the occurrence, and risk factors for Leptospira infection among livestock species and environmental sources in Uganda. Method From a nationwide cross-sectional survey in major livestock slaughter facilities, we performed a real-time PCR test on 2,063 livestock kidney samples from 844 cattle, 761 pigs, 341 goats,117 sheep; and on 93 small mammals. Small mammals (rodents and shrews) were trapped at slaughter facilities and communities within a 500metre radius from slaughter facilities. Age, sex, breed and origin of each sampled animal were noted. Leptospira prevalence was estimated and risk factors for infection among livestock species determined using univariate logistic regression model. Results Leptospira infection was detected in 43 of 2,063 livestock samples tested (2.08%, 95% C.I = 1.52-2.80). Infection was highest in sheep (5.13% C.I = 2.25-10.80), 3.32% (95% C.I = 2.26-4.75) in cattle, 1.76% (95% C. I=0.77-3.70) in goats, and 0.39 (95% C.I = 0.10-1.13) in pigs. Pigs were significantly less infected compared to all other species (p‐value= 0.0008). Indigenous livestock breeds were more infected (p‐value =0.005) compared to their exotic and crossed counterpart. Additionally, older livestock species were significantly infected than the younger ones (p‐value = 0.052). None of the small mammals tested positive. Conclusion Livestock in Uganda reserve pathogenic Leptospira species, with sheep and cattle especially of indigenous breed being more significant reservoirs. Small mammals may play a limited role in Leptospira maintenance and transmission in Uganda

Prevalence of tuberculous lesion in cattle slaughtered in Mubende district, Uganda

BACKGROUND: The aim of this study was to estimate the prevalence of gross pathology suggestive of bovine tuberculosis (TB-like lesions) and evaluate animal’s characteristics associated with the risk of having bovine TB-like lesions among cattle slaughtered in Mubende district in the Uganda cattle corridor. METHOD: We conducted a cross sectional study in which 1,576 slaughtered cattle in Mubende district municipal abattoir underwent post-mortem inspection between August 2013 and January 2014. The presence of bovine TB-like lesions in addition to the animal’s sex, age, breed, and sub-county of origin prior to slaughter were recorded. Associations between the presence of bovine TB-like lesions and animal’s age, sex, breed, and sub-county of origin prior to slaughter were initially analysed using a univariable approach with the chi-square test, and subsequently with a multivariable logistic regression model to assess the combined impact of these animal characteristics with the risk of having a bovine TB-like lesion. Additionally, and as a secondary objective, tissue samples were collected from all carcases that had a bovine TB-like lesion and were processed using standard Mycobacterium culture and identification methods. The culture and acid fast positive samples were tested using Capilia TB-neo® assay to identify Mycobacterium tuberculosis complex (MTC). RESULTS: Of 1,576 carcasses inspected, 9.7% (153/1,576) had bovine TB-like lesions from which Mycobacterium spp and Mycobacterium Tuberculosis Complex (MTC) were isolated in 13 (8.4%) and 12 (7.8%) respectively. Bovine TB-like lesions were more likely to be found in females (OR = 1.49, OR 95% CI: 1.06–2.13) and in older cattle (OR = 2.5, 95% CI: 1.64–3.7). When compared to Ankole cattle, Cross breed (OR = 6.5, OR 95% CI: 3.37–12.7) and Zebu cattle (OR = 2.57, 95% CI: 1.78–3.72) had higher odds of having bovine TB-like lesions. Animals from Kasanda (OR = 2.5, 95% CI: 1.52–4.17) were more likely to have bovine TB-like lesions than cattle from Kasambya. CONCLUSIONS: The findings of study reveals that approximately one in ten slaughtered cattle presents with gross pathology suggestive of bovine TB in Mubende district in the Uganda cattle corridor district, however, we isolated MTC in only 8.4% of these bovine TB-like lesions. Therefore, there is a need to understand the cause of all the other bovine TB-like lesions in order to safe guard diagnostic integrity of meat inspection in Uganda

Surveillance of climate-sensitive zoonotic diseases: Leptospirosis at livestock slaughterhouses in three regions of Uganda

Leptospirosis is an important bacterial zoonosis worldwide and is disproportionately associated with low-income settings and with extreme weather events due to climate change. Transmission to humans often occurs when infected rodents and domestic animals contaminate the environment via urine as the bacteria preferentially colonise kidneys. Surveillance of leptospirosis at slaughterhouses can therefore be useful in providing information on vast areas of a country and screening for diseases that are not considered during animal inspections. We determined the prevalence of Leptospira bacteria in the kidneys of 2,030 livestock kidney samples (820 cattle, 761 pigs, 335 goats, 114 sheep), and 117 small mammals by realtime PCR in a cross-sectional survey of slaughter facilities in three regions in Uganda. We extracted DNA and performed real-time polymerase chain reaction (PCR) tests targeting the lipL32 gene for pathogenic leptospires. Positive samples with cycle threshold values below 38 were further characterised using single locus sequence typing (SLST) to determine likely genomospecies. PCR products were sequenced by Eurofins Genomics (Ebersberg, Germany) and identification of genomospecies was done using the basic local alignment search tool (BLAST). Multi-locus sequencing typing (MLST) was performed on selected SLST-positive samples to determine sequence types (ST) and likely serogroups. The allelic profiles were analysed using Bionumerics software and the sequence types were determined using the PubMLST database. An overall prevalence of pathogenic leptospires of 2.58 % (95 % confidence intervals [CI]: 1.89–3.42) was observed, with sheep having the highest prevalence (6.12 % CI: 2.69–12.89), followed by cattle (4.25 %, 95 % CI: 2.91–5.98), goats (2.08 %, 95 % CI=0.91–4.38), and pigs (0.46 %, 95 % CI = 0.12–1.31) in decreasing order. The genomospecies L. borgpetersenii (11 in cattle and one in goat), L. kirschneri (five in cattle and four in sheep) and L. interrogans (one in a pig) were determined. Preliminary MLST results on one sample reveal L. kirschneri ST62 which is related to serogroup Grippotyphosa. Surveillance of important zoonoses using slaughterhouses as sentinels has the potential to offer essential information on the epidemiology of important zoonotic diseases in Uganda