Modelling seasonal household variation in harvested rainwater availability: a case study in Siaya County, Kenya

Rainwater harvesting reliability, the proportion of days annually when rainwater demand is fully met, is challenging to estimate from cross-sectional household surveys that underpin international monitoring. This study investigated the use of a modelling approach that integrates household surveys with gridded precipitation data to evaluate rainwater harvesting reliability, using two local-scale household surveys in rural Siaya County, Kenya as an illustrative case study. We interviewed 234 households, administering a standard questionnaire that also identified the source of household stored drinking water. Logistic mixed effects models estimated stored rainwater availability from household and climatological variables, with random effects accounting for unobserved heterogeneity. Household rainwater availability was significantly associated with seasonality, storage capacity, and access to alternative improved water sources. Most households (95.1%) that consumed rainwater faced insufficient supply of rainwater available for potable needs throughout the year, with intermittencies during the short rains for most households with alternative improved sources. Although not significant, stored rainwater lasts longer for households whose only improved water source was rainwater (301.8 ± 40.2 days) compared to those having multiple improved sources (144.4 ± 63.7 days). Such modelling analysis could enable rainwater harvesting reliability estimation, and thereby national/international monitoring and targeted follow-up fieldwork to support rainwater harvesting.

Evaluation of dog vaccination schemes against rabies in Kinshasa, Democratic Republic of the Congo

The traditional rabies control strategy based on annual mass vaccination of dogs appears to be costly and cumbersome. Given the existence of different risk zones for rabies transmission, the present study aimed at proposing risk-based vaccination schemes by considering canine population dynamics as well as vaccine efficacy and duration of immunity (DOI). The capital of the Democratic Republic of the Congo (RDC), Kinshasa, was chosen as study site. The turnover rate of dogs was used to assess their population dynamics in two low-roaming (<25 % of dogs are roaming) and in two high-roaming zones (>75 % of dogs are roaming). The sero-conversion rate was assessed in response to primo-vaccination in three age groups: 24 puppies (≤3months), 37 juveniles (4-12 months) and 22 adult dogs. The DOI was evaluated serologically by revaccinating dogs previously vaccinated since 1-2 years (n = 31), 2-3 years (n = 12) or 3-7.5 years (n = 4). Rapid Fluorescent Focus Inhibition Test was used to quantify antibodies. These data were used to implement vaccination outcome models.The turnover rate was twice as high in high-roaming zones (36 %) as that in lowroaming zones (17 %). Irrespective of roaming level, 75 % of dogs were less than 3 years old. The vaccine was equally effective in puppies (96 %), juvenile (97 %) and adult dogs (100 %, p = 0.24). The vaccine was effective in 93 % (11/12) of puppies without pre-vaccinal protective titers (≥0.5 IU/mL). The anamnestic response was strong within 5-8 days upon the booster vaccination, in 96 % (45/47) of dogs reported vaccinated 1-7.5 years before. This suggests that the vaccine provided a long-term protection (≥3 years) which is likely to occur in 75 % of dogs in Kinshasa.Hypothesizing a vaccination stop, the vaccination outcome model allowed to estimate the time point after which vaccination coverage would drop below 40 % in function of dog population turnover rate. The systematic vaccination of puppies as well as annual vaccination of dogs aged between 3 and 15 months or annual vaccination of all unvaccinated dogs aged more than 3 months of age appeared as valuable alternative to systematic annual mass vaccination.In conclusion, this study developed a vaccination outcome model pointing out the impact of dog population dynamics and of effective duration of immunity. It appears as a promising tool for designing cost-effective rabies vaccination campaigns.

Animal bites and post-exposure prophylaxis in Central-West Tunisia: a 15-year surveillance data

BACKGROUND

Rabies is a disease that still exists in developing countries and leads to more fatalities than other zoonotic diseases. Our study aimed to describe the profile of human exposures to animals over fifteen years and to assess the post-exposure prophylaxis (PEP) practices in the governorate of Kasserine (Tunisia) on pre- and post-revolution (2011).

METHODS

We carried out a descriptive study using surveillance data from a region in Central-West Tunisia. All humans exposed to animals, residents in Kasserine Governorate and declared to the regional directorate of primary health care (RDPH) from January 1st, 2004 to December 31st, 2018 were included.

RESULTS

A total of 45,564 cases of human exposures to animals were reported over the fifteen-year period of the study with an annual average of 3089.2 ± 403.1. The standardized incidence rate (SIR) of human exposures to animals was 694 per year per 100,000 inhabitants (inh). The most listed offending animal was the dog (91.3%) and the most reported type of exposure was bites (63.7%). The trend in human exposures to animals increased significantly over time. The number of exposures by vaccinated dogs decreased significantly and by unvaccinated and stray dogs increased steeply. When comparing pre-and post-revolution periods, the yearly average of animal exposures post-2011 was significantly greater than the average prior to 2011 (3200 ± 278.5 vs 2952.8 ± 483) (p < 0.001). The yearly average of animal bites post-2011 was significantly greater than the average prior to 2011 (2260.5 ± 372.1 vs 1609.8 ± 217.9) (p < 0.001). The average number of vaccine doses per animal exposure was 2.4. Concerning PEP protocols, protocol A (2 and 3 doses) was indicated in 79% of animal exposures cases. From 2004 to 2018, a downward trend was noted for protocol A (r = - 0.29, p < 0.001) and an upward trend for protocol B (3 and 5 doses) (r = 0.687, p < 0.001). During our study period, 5 fatal cases of human rabies were declared.

CONCLUSION

Rabies remains a major public health problem in Tunisia. The political dynamics had an impact on the health care system and rabies control. Preventive measures should be applied adequately to decrease the burden of this disease.

Who let the dogs out? Exploring the spatial ecology of free-roaming domestic dogs in western Kenya

The spatial ecology of free-roaming dogs determines their role in the transmission of zoonoses. This study describes the geographic range of and identifies sites frequently visited by free-roaming domestic dogs in western Kenya. Eight sites in Busia county, western Kenya, were selected. At each site, ten dog-keeping households were recruited, a questionnaire was administered, and a GPS logger was fixed around the neck of one dog in each household. Loggers were programmed to capture the dog's position every minute, for five consecutive days. Individual summaries of GPS recordings were produced, and the daily distance traveled was calculated. 50% and 95% utilization distribution isopleths were produced, and the area within these isopleths was extracted to estimate the size of the core and extended Home Ranges (HRs), respectively. Linear regression analyses were performed to identify factors associated with the movement parameters. The centroid points of the 10, 50, and 90% isopleths were reproduced, and the corresponding sites identified on the ground. Seventy-three dogs were included in the final analyses. The median daily distance traveled was 13.5km, while the median core and extended HRs were 0.4 and 9.3 ha, respectively. Older dogs had a larger extended HR and traveled more daily, while the effect of sex on dog movement depended on their neutering status. Dogs spent most of their time at their household; other frequently visited sites included other household compounds, fields, and rubbish dumps. One of the centroids corresponded to a field located across the international Kenya-Uganda border, emphasizing the fluidity across the border in this ecosystem. Multiple dogs visited the same location, highlighting the heterogeneous contact networks between dogs, and between dogs and people. The field data presented are of value both in understanding domestic dog ecology and resource utilization, and in contextualizing infectious and parasitic disease transmission models.