Time-course investigation of infection with a low virulent Pasteurella multocida strain in normal and immune-suppressed 12-week-old free-range chickens.

Twelve-week-old indigenous chickens, either immune-suppressed using dexamethasone (IS) or non-immune-suppressed (NIS), were challenged with a low virulent strain, Pasteurella multocida strain NCTC 10322(T), and developed clinical signs and pathological lesions typical of chronic fowl cholera. NIS birds demonstrated much more severe signs of fowl cholera than IS birds. With few exceptions, signs recorded in IS and NIS birds were of the same types, but significantly milder in the IS birds, indicating that immune suppression does not change the course of infection but rather the severity of signs in fowl cholera. P. multocida signals by fluorescent in situ hybridization (FISH) were observed between 1 h and 14 days in the lungs, trachea, air sacs, liver, spleen, bursa of Fabricius and caecal tonsils, while signals from other organs mostly were observed after 24 h. More organs had FISH signals in NIS birds than in IS birds and at higher frequency per organ. Many organs were positive by FISH even 14 days post infection, and it is suggested that these organs may be likely places for long-term carriage of P. multocida following infection. The present study has demonstrated the spread of P. multocida in different tissues in chickens and distribution of lesions associated with chronic fowl cholera, and pointed to a decrease of pathology in IS birds. Since dexamethasone mostly affects heterophils, the study suggests that these cells play a role in the development of lesions associated with chronic fowl cholera in chickens.

Bacterial contamination of kale (Brassica oleracea Acephala) along the supply chain in Nairobi and its environment.

OBJECTIVE: To assess the microbiological safety of kale (Brassica oleracea Acephala) produced from farms and those sold at the markets with special focus on coliforms, E.coli and Salmonella. DESIGN: A cross sectional study. SETTING: Peri-Urban farms (in Athi River, Ngong and Wangige), wet markets (in Kawangware, Kangemi and Githurai), supermarkets and high-end specialty store both within Nairobi city. RESULTS: Mean coliform count on vegetables from farms were 2.6 x 10(5) +/- 5.0 x 10(5) cfu/g while those from the wet markets were 4.6 x 10(6) +/- 9.1 x 10(6) cfu/g, supermarkets, 2.6 x 10(6) +/- 2.7 x 10(6) and high-end specialty store 4.7 x 10(5) +/- 8.9 x 10 (5). Coliform numbers obtained on kales from the wet markets and supermarkets were significantly higher (p < 0.05) compared to those from farms, while kale samples purchased from high-end specialty store had similar levels of coliform loads as those from the farms. E. coli prevalence in the wet markets, supermarkets and high-end specialty store were: 40, 20 and 20%, respectively. Salmonella was detected on 4.5 and 6.3% of samples collected from the farms in Wangige and wet market in Kawangware, respectively. Fecal coliforms in water used on farms (for irrigation) and in the markets (for washing the vegetables) exceeded levels recommended by World Health Organization (WHO) of 10(3) organisms per 100 milliliter while Salmonella was detected in 12.5% of washing water samples collected from Kangemi market. CONCLUSION: Poor cultivation practices and poor handling of vegetables along the supply chain could increase the risk of pathogen contamination thus puting the health of the public at risk, therefore good agricultural and handling practices should be observed.

Isolation, Characterization, and Quantification of Bacteria from African Sausages Sold in Nairobi County, Kenya.

African sausages are local popular delicacies in Kenya. Demand for these sausages has resulted in this delicacy's vendors being on the increase. However, health risk posed to unsuspecting consumers of African sausages sold in informal, unhygienic make shift road-side kiosks in major cities of Kenya is largely unknown. A descriptive study was designed to isolate, characterize and quantify bacteria from African sausages sold in Nairobi County. A total of hundred (100) African sausages (62 roasted and 38 nonroasted) were conveniently collected from three meat eatery points of Westlands, Kangemi slum, and Pangani estates. Five genera of bacteria, namely, Staphylococcus spp. at 50.4%, Bacillus spp. at 19.5%, Streptococcus spp. 9.8%, Proteus spp. 2.4%, and E. coli spp. at 1.6%, were isolated from 80 African sausage samples. The total aerobic bacterial count range was between 1.0-9.9x101 and 1.0-9.9x107 log cfu/g with 37 samples having total aerobic bacterial count of between 1.0-9.9 x104 and 1.0-9.9 x107 log cfu/g. There was no significant difference (p>0.05) in distribution of isolates and total aerobic bacterial count across geographical sites studied among the roasted and nonroasted African sausages. This study has demonstrated presence of bacteria in African sausages which are potentially zoonotic to humans. Comprehensive study is needed to sample more eatery meat points in Nairobi and other areas in order to demonstrate pathogenic attributes of these isolates and establish the respective total aerobic bacterial count. There is also need to establish the sources of bacteria due to high total aerobic bacterial count determined in the current study.

Stinging nettle and neem enhance antibody response to local killed and imported live infectious bursal disease vaccines in indigenous chicken in Kenya.

Immune responses are critical for protection of chickens from infectious bursal disease (IBD). In this study, the antibody response-enhancing effect of drinking water supplementation of 1% stinging nettle and neem on different IBD vaccines and vaccination regimes was evaluated, using 36 (n = 36) specific antibody negative indigenous chicks. The birds were allocated into 3 groups as follows: 1A-C, 2A-C, and 3A-B, while group 3C acted as the unvaccinated non-supplemented control. A local inactivated K1 and imported live attenuated D78 IBD vaccines were given to groups 1A-C and 3A-B at 14 and 28 d of age, respectively. A combination of K1 and D78 vaccines was given 30 d apart to groups 2A and 2B (D78 at 14 and 21 d and K1 at 44 d of age) and on the same d to group 2C at 14 and 28 d of age. Stinging nettle was given in water to groups 1B, 2B, and 2C, and neem to groups 1C, 2A, and 3B. Birds were bled weekly and immune responses monitored using indirect ELISA. Both neem and stinging nettle had antibody response-enhancing effects in groups 1B and 1C, receiving the local inactivated K1 vaccine. There were significant differences (P < 0.05) in antibody titers between groups 1A and 2C. Stinging nettle induced earlier onset of high antibody responses in group 2C and persistent titers (>3.8 log10) from the third week in group 2B. Imported live D78 vaccine induced higher antibody titers compared to the local inactivated K1 vaccine. Groups 2B and 2C receiving a combination of the local K1 and imported live attenuated D78 vaccines had the highest antibody titers. Adoption of stinging nettle supplementation and a prime-boost program involving use of a local virus isolates-derived vaccine is recommended.

Antimicrobial Resistance Profiles of Bacteria Isolated from the Nasal Cavity of Camels in Samburu, Nakuru, and Isiolo Counties of Kenya.

This study was designed to determine antimicrobial resistance profiles of bacteria isolated from the nasal cavity of healthy camels. A total of 255 nasal samples (swabs) were collected in Isiolo, Samburu, and Nakuru counties, Kenya, from which 404 bacterial isolates belonging to various genera and species were recovered. The bacterial isolates included Bacillus (39.60%), coagulase-negative Staphylococcus (29.95%), Streptococcus species other than Streptococcus agalactiae (25.74%), coagulase-positive Staphylococcus (3.96%), and Streptococcus agalactiae (0.74%). Isolates were most susceptible to Gentamicin (95.8%), followed by Tetracycline (90.5%), Kanamycin and Chloramphenicol (each at 85.3%), Sulphamethoxazole (84.2%), Co-trimoxazole (82.1%), Ampicillin (78.9%), and finally Streptomycin (76.8%). This translated to low resistance levels. Multidrug resistance was also reported in 30.5% of the isolates tested. Even though the antibiotic resistance demonstrated in this study is low, the observation is significant, since the few resistant normal flora could be harboring resistance genes which can be transferred to pathogenic bacteria within the animal, to other animals' bacteria and, most seriously, to human pathogens.

Prevalence of Subclinical Mastitis and Distribution of Pathogens in Dairy Farms of Rubavu and Nyabihu Districts, Rwanda.

A cross-sectional study was conducted from May 2016 to January 2017 in Rubavu and Nyabihu districts, Western Rwanda, aiming at estimating the prevalence of subclinical mastitis (SCM) and identifying its causative bacteria. Management practices and milking procedures were recorded through a questionnaire. 123 crossbreed milking cows from 13 dairy farms were randomly selected and screened for SCM using California Mastitis Test (CMT). Composite CMT positive milk samples were processed for bacterial isolation and identification. The overall SCM prevalence at cow level was 50.4%. 68 bacterial isolates were identified by morphological and biochemical characteristics. They included, Coagulase Negative Staphylococci (51.5%), Staphylococcus aureus (20.6%), Streptococcus species (10.3%), Bacillus species (10.3%), Streptococcus agalactiae (5.8%), and Escherichia coli (1.5%). About 67.1% of the farmers checked for mastitis; of these, 58.9% relied on clinical signs and only 6.8% screened with CMT. Only 5.5% and 2.7% of the farmers tried to control mastitis using dry cow therapy and teat dips, respectively. Thus, to reduce the prevalence of SCM, farmers in the study area need to be trained on good milking practices, including regular use of teat dips, application of dry cow therapy, and SCM screening. This will improve their sales and their financial status.

Detection and Genome Analysis of a Lineage III Peste Des Petits Ruminants Virus in Kenya in 2011.

In May 2011 in Turkana County, north-western Kenya, tissue samples were collected from goats suspected of having died of peste des petits ruminant (PPR) disease, an acute viral disease of small ruminants. The samples were processed and tested by reverse transcriptase PCR for the presence of PPR viral RNA. The positive samples were sequenced and identified as belonging to peste des petits ruminants virus (PPRV) lineage III. Full-genome analysis of one of the positive samples revealed that the virus causing disease in Kenya in 2011 was 95.7% identical to the full genome of a virus isolated in Uganda in 2012 and that a segment of the viral fusion gene was 100% identical to that of a virus circulating in Tanzania in 2013. These data strongly indicate transboundary movement of lineage III viruses between Eastern Africa countries and have significant implications for surveillance and control of this important disease as it moves southwards in Africa.

Isolation of Infectious Bursal Disease Virus Using Indigenous Chicken Embryos in Kenya.

Infectious bursal disease virus (IBDV) isolates were recovered from outbreaks to initiate activities towards developing a local vaccine strain. Use of indigenous chicken embryos was exploited to determine their potential, promote utilization of local resources for research, and enhance household economic activities. Bursa of Fabricius (BFs) samples from outbreaks shown to be IBDV positive was homogenized and inoculated in 4-week-old specific pathogen-free (SPF) IBDV seronegative white leghorn chicks. The harvested virus was inoculated into 11-day-old indigenous chicken embryos that were IBDV seronegative and passaged serially three times after which they were inoculated into 4-week-old indigenous chicks to test for presence and virulence of propagated virus. Out of 153 BFs collected from outbreaks, 43.8% (67/153) were positive for IBDV antigen and 65.7% (44/67) caused disease in SPF chicks. The embryo mean mortalities were 88% on primary inoculation, 94% in 1st passage, 91% in 2nd passage, and 67% in 3rd passage. After the third passage in embryos all the 44 isolates were virulent in 4-week-old indigenous chicks. The results show that indigenous chicken embryos support growth of IBDV and can be used to propagate the virus as an alternative viral propagating tool for respective vaccine preparation.

Occurrence of atypical fowlpox in poultry farms in Kenya.

Atypical fowlpox occurred in several poultry farms in Kenya. On two occasions layers had their eyes closed and egg production dropped. Fowlpox virus was isolated from lesions on the inner surfaces of the closed eyelids. Other chickens had lesions covered by yellow caseous necrotic material in the mouth, around the epiglottis, and in the trachea and choanae. Typical proliferative cutaneous lesions were observed in birds of all ages in other flocks examined. Fowlpox virus was recovered from both cutaneous and diphtheritic lesions. The infected chorioallantoic membranes had focal hyperplastic lesions containing pink-staining intracytoplasmic inclusion bodies in most cells. Transmission studies showed that the virus was highly virulent to susceptible chickens.

Comparison of immune responses of two Salmonella gallinarum strains viewed as possible vaccines for fowl typhoid in Kenya.

The immune responses of two S. gallinarum strains, L46 and CN 180, were compared in 15-week-old cockerels. The humoral and cell-mediated immune responses were assayed by means of the indirect haemagglutination test (IHA) and the macrophage migration inhibition test (MIT), respectively. Birds were vaccinated with the two vaccines, respectively, and bled for sera (for IHA) and cells (for MIT) every week up to the seventh week, post vaccination, then every alternate week, three times, and later once every month, for a total period of 37 weeks. Strain L46 was found to induce an immune response that was very similar to that of CN 180. Both gave good humoral and cellular responses.

Role of plasmids in the virulence of enteric bacteria.

Plasmids have been shown to play an important role in the pathogenecity of most enterobacteria. Their involvement in various enterobacteria was discovered at different times and there is resemblance in the type of toxins produced by a number of enterobacteria and in the genes responsible for the production of the toxins and invasiveness. This indicates a spread of a factor from one bacterial strain to another, thus enabling the recipient to demonstrate the characteristic coded for. This factor may be the plasmid or chromosomal portion that codes for the characteristic.

Resistance of E. coli strains, recovered from chickens to antibiotics with particular reference to trimethoprim-sulfamethoxazole (septrin).

Thirty-seven strains of E. coli recovered from cases of septicaemia in chicken were tested for sensitivity to 6 antibiotics. Minimum inhibitory concentration (MIC) determinations done on the strains showed resistance to trimethoprim-sulfamethoxazole (septrin) (100%), ampicillin (62.2%), tetracycline (51.4%), kanamycin (13.5%) and gentamicin (2.7%). All were sensitive to chloramphenicol. Conjugation studies showed easy transfer of the resistance factor for septrin to the recipient sensitive strain, K12F-, a 60 megadalton plasmid was transferred in most of the cases (a number of plasmids moved across to K12F- strains). Septrin was chosen as a referral antibiotic because it is used extensively for treating diarrhoeal cases in children in Kenya. The results expressed the possibility of the chicken being the possible source of the septrin resistance gene (plasmid) for humans, and vice versa.

Plasmid profiles of E. coli, Salmonella and shigella organisms isolated in Kenya.

A number of serotypable E. coli, Salmonella and Shigella strains isolated from three districts in Kenya were investigated for carriage of plasmids. This was done through extraction of plasmids and separating them by electrophoresis on agarose. Most of the strains investigated showed presence of plasmids. The E. coli isolates had plasmids ranging in number from 1 to 5, the most common number was 2. The plasmid sizes ranged from 80 to 30 megadalton, the commonest of the heavy plasmids were 70 megadalton. The Shigella isolates had plasmids ranging in number from 1 to 3, the most common number was 1. The plasmid sizes ranged from 80 to 3.5 megadalton, the commonest of the heavy plasmids were 70 megadalton. Various plasmid-sizes have been published as being responsible for pathogenicity.

Sensitivity of Listeria species, recovered from indigenous chickens to antibiotics and disinfectants.

BACKGROUND: Resistance of bacteria to antibiotics and disinfectants has been reported widely in the world. Listeria monocytogenes is no exception, although normally it tends to be variably sensitive to many antibiotics and disinfectants. OBJECTIVES: To assess the susceptibility of Listeria isolates recovered from indigenous chickens to commonly used antimicrobials. DESIGN: Nine Listeria isolates recovered from village chickens were tested for sensitivity to commonly used antibiotics and disinfectants and compared with Listeria monocytogenes type strains (L028 and DGH), Staphylococcus aureus NCTC 6571 and Escherichia coli ATCC 25922. SUBJECTS: Nine Listeria isolates. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Susceptibility to eight antibiotics and seven disinfectants. RESULTS: The nine Listeria isolates were sensitive to gentamycin (100%), kanamycin (88.9%), tetracycline (77.8%), cotrimoxazole (66.7%), chloramphenicol (66.7%) and resistant to ampicillin, augmentin and cefuroxime. There was no difference between the antibiotic sensitivity to the various Listeria isolates and Listeria monocytogenes type strains (P > 0.05). The isolates were sensitive to disinfectants; A (100%), B (88.9%), D (77.8%), E (77.8%) but resistant to, CF, and G. There was significant difference between the resistance of Listeria isolates to the various disinfectants at the varied dilutions and the resistance at the recommended user--dilution (P < 0.00293). CONCLUSION: This study has shown that some of the Listeria isolates were resistant to most common antimicrobial agents except gentamycin and disinfectant A. Hence the need to consider this resistance pattern for effective treatment and control of listeriosis.

Carrier status for Listeria monocytogenes and other Listeria species in free range farm and market healthy indigenous chickens and ducks.

BACKGROUND: Listeria organisms are documented to be zoonotic; one of the sources of infection is the domestic fowl where it could occur as in apparent infection. The carriage of Listeria monocytogenes and other Listeria in indigenous birds has not been documented in Kenya. OBJECTIVE: To establish whether healthy looking indigenous chickens and ducks could be carriers of Listeria monocytogenes and other Listeria species. DESIGN: Field survey of indigenous chickens and ducks in three districts of Kenya. SETTING: Embakasi and Dagoreti divisions in Nairobi district; Athi river division in Machakos district; and Ngong division in Kajiado district, in Kenya. SUBJECTS: One hundred and thirty six indigenous chickens and 39 ducks reared under free range scavenging system in Nairobi, Machakos and Kajiado districts, in Kenya, were sampled. METHODS: In surveying the birds, the cloacal and pharyngeal swabs were taken from each bird separately using sterile cotton--tipped applicator swabs. The swabs in saline were transported in a coolbox to the laboratory for bacterial isolation and characterization. INTERVENTIONS: None (only compared farmed and the traded birds). MAIN OUTCOME MEASURES: Isolation of Listeria species and pathogenicity of Listeria isolates. RESULTS: Two Listeria monocytogenes and seven other Listeria species were recovered from the oropharyngeal swab samples of farm and market chickens but none from respective cloacal swabs. No Listeria was recovered from either oropharyngeal or cloacal swabs of farmed duck and slaughter chickens. Traded chickens yielded more Listeria isolates as compared to farmed chickens. CONCLUSION: This study shows that indigenous chickens in Kenya are carriers of Listeria monocytogenes and other Listeria species.

Occurrence of dermatomycosis (ringworm) due to Trichophyton verrucosum in dairy calves and its spread to animal attendants.

Persistent dermatomycosis (ringworm) caused by Trichophyton verrucosum affected 20 dairy calves aged between 3 months and 1 year and housed together. The infection also spread to 2 animal attendants working among the calves. The major clinical lesions observed on the affected calves were extensive alopecia and/or circumscribed thick hairless skin patches affecting the head, neck, flanks and limbs. The observed lesions persisted for more than 17 weeks and most of the calves did not respond to topical treatment with various anti-fungal drugs within the anticipated period of 9 weeks. Two animal attendants developed skin lesions that were circumscribed and itchy and there was good response to treatment following the application of anti-fungal skin ointment. Although ringworm in dairy animals in Kenya has not previously been associated with spread to humans, the potential is evident from this report.

Pasteurella multocida in scavenging family chickens and ducks: carrier status, age susceptibility and transmission between species.

Pasteurella multocida causes fowl cholera, a highly contagious and severe disease in chickens and water fowls. The disease is not well described in less intensive production systems, including scavenging family poultry production in developing countries. P. multocida was isolated from 25.9% of healthy-looking ducks and 6.2% of chickens from free-range family poultry farms and at slaughter slabs at market. On experimental infection with 1.2 to 2.0 x 10(8) organisms of the P. multocida type strain (NCTC 10322(T)), 12-week-old chickens expressed fowl cholera clinical signs significantly more times (372 signs) than those of 4-week-old, 8-week-old and 16-week-old chickens (173, 272 and 187 signs) and more signs were severe. In family ducks the 8-week-old birds expressed clinical signs significantly more times (188 signs) than those of the other age groups (117, 80, and 83 signs, respectively) and severe signs were more frequent. P. multocida transmitted from seeder birds (n=12) to sentinel birds (n=30), which developed clinical signs, and in some cases lesions of fowl cholera allowed bacterial re-isolation, whether infected ducks served as seeders for chickens or chickens served as seeder for ducks. This study has documented the occurrence of P. multocida among healthy-appearing family poultry in a tropical setting, and demonstrated that age susceptibility is highest in 12-week-old family chickens and 8-week-old family ducks when challenged with a low-virulent strain of P. multocida. It has further demonstrated that cross-transmission of fowl cholera may happen between family ducks and chickens, and vice versa.