A Risk Assessment of Aflatoxin M1 Exposure in Low and Mid-Income Dairy Consumers in Kenya

Aflatoxin M1 (AFM1), a human carcinogen, is found in milk products and may have potentially severe health impacts on milk consumers. We assessed the risk of cancer and stunting as a result of AFM1 consumption in Nairobi, Kenya, using worst case assumptions of toxicity and data from previous studies. Almost all (99.5%) milk was contaminated with AFM1. Cancer risk caused by AFM1 was lower among consumers purchasing from formal markets (0.003 cases per 100,000) than for low-income consumers (0.006 cases per 100,000) purchasing from informal markets. Overall cancer risk (0.004 cases per 100,000) from AFM1 alone was low. Stunting is multifactorial, but assuming only AFM1 consumption was the determinant, consumption of milk contaminated with AFM1 levels found in this study could contribute to 2.1% of children below three years in middle-income families, and 2.4% in low-income families, being stunted. Overall, 2.7% of children could hypothetically be stunted due to AFM1 exposure from milk. Based on our results AFM1 levels found in milk could contribute to an average of −0.340 height for age z-score reduction in growth. The exposure to AFM1 from milk is 46 ng/day on average, but children bear higher exposure of 3.5 ng/kg bodyweight (bw)/day compared to adults, at 0.8 ng/kg bw/day. Our paper shows that concern over aflatoxins in milk in Nairobi is disproportionate if only risk of cancer is considered, but that the effect on stunting children might be much more significant from a public health perspective; however, there is still insufficient data on the health effects of AFM1.Peer reviewe

The N-methyl-D-aspartate (NMDA)-type glutamate receptor GluRepsilon2 is important for delay and trace eyeblink conditioning in mice.

It has been proposed that the N-methyl-d-aspartate (NMDA)-type glutamate receptor (GluR) plays an important role in synaptic plasticity, learning, and memory. The four GluRepsilon (NR2) subunits, which constitute NMDA receptors with a GluRzeta (NR1) subunit, differ both in their expression patterns in the brain and in their functional properties. In order to specify the distinct participation of each of these subunits, we focused on the GluRepsilon2 subunits, which are expressed mainly in the forebrain. We investigated delay and trace eyeblink conditioning in GluRepsilon2 heterozygous mutant mice whose content of GluRepsilon2 protein was decreased to about half of that in wild-type mice. GluRepsilon2 mutant mice exhibited severe impairment of the attained level of conditioned response (CR) in the delay paradigm, for which the cerebellum is essential and modulation by the forebrain has been suggested. Moreover, GluRepsilon2 mutant mice showed no trend toward CR acquisition in the trace paradigm with a trace interval of 500 ms, in which the forebrain is critically involved in successful learning. On the other hand, the reduction of GluRepsilon2 proteins did not disturb any basic sensory and motor functions which might have explained the observed impairment. These results are different from those obtained with GluRepsilon1 null mutant mice, which attain a normal level of the CR but at a slower rate in the delay paradigm, and showed a severe impairment in the trace paradigm. Therefore, the NMDA receptor GluRepsilon2 plays a more critical role than the GluRepsilon1 subunit in classical eyeblink conditioning

Cattle with a low bovine leukemia virus proviral load are rarely an infectious source

Bovine leukemia virus (BLV) is an etiological agent of fatal B-cell leukemia and malignant lymphoma in cattle. Cattle with higher BLV proviral loads represent a higher risk of both horizontal and vertical transmission. Therefore, quantifying the proviral load of BLV is important in identifying major infectious sources and protecting BLV-free cattle from exposure to infected cattle. In this study, we confirmed that cattle with very low BLV proviral loads did not transmit the virus to virus-free cattle under conventional conditions. We observed a total of 7 tests in which a BLV-infected bull was allowed to cohabit with 57 to 92 BLV-free cattle for 12 or 22 months. We then evaluated the frequency of viral transmission. A BLV-infected bull with a “very low proviral load” (i.e., fewer than 100 proviral copies/50 ng of genomic DNA) did not transmit the virus to any virus-free cattle in 2 out of 2 tests. However, a BLV-infected bull with a “low proviral load” (i.e., 100 to 500 copies/50 ng) transmitted the virus to a total of 3 virus-free cattle in 2 out of 5 tests. These results suggest that BLV-infected cattle with “very low proviral loads” do not transmit the virus under conventional conditions, while cattle with “low proviral loads” can transmit the virus, although at low rates. We believe that the results of this study will promote the construction of effective measures to prevent BLV infection and control the spread of BLV

Towards better-informed consent: research with livestock-keepers and informal traders in East Africa

With the rise of the One Health paradigm, ethicists have called for new research approaches, considering the interdependent relationships of humans, animals, and their environment. These relationships can be particularly complex within resource-poor, smallholder livestock systems, necessitating a rigorous informed-consent process. Little has been published on informed consent beyond human-subject research. This paper outlines two studies on informed consent, for research identifying diseases of animal and human importance, within smallholder livestock value chains.Firstly, a randomized independent-group study compared three communication tools (written, cartoons, and photographs) for informing 22 Tanzanian livestock-keepers before seeking their consent. A significant difference in comprehension and engagement in the informed-consent process was found between tools, and cartoons had the highest (i.e. best combined comprehension and engagement) scores. Most (21 out of 22) farmers answered half or more the questions correctly, but none were able to answer all questions. Comprehension testing allowed identification of common misunderstandings, such as immediate benefits the farmers would receive and the process to be used for relaying research results. Dialogue stimulated by cartoons and photographs allowed researchers to determine and respond to participants' varied relationships with their livestock.The second study assessed preferred methods for indicating consent among informal-sector milk vendors in Nairobi, Kenya. Of consenting participants, 61% (140/230) indicated consent verbally, 39% (90/230) signed consent and none chose thumbprint. There was a significant enumerator-effect on both overall consent and the methods chosen.Several of these findings echo those published in human-medical research. Additionally, highlighted here is the importance of facilitating dialogue during the informed-consent process in One Health research, for a more nuanced understanding of relationships between humans, animals, and their environment. Also discussed is how a requirement to sign consent forms might limit consent among workers in informal markets, which are commonly studied in One Health research. We suggest expansion of these, and development of further, studies towards improving consent processes in One Health research