A cross-sectional study was carried out to determine the profiles, gross tissue, and microbial integrity of cadavers in medical schools in SWU from January to March 2024.

The study was carried out in medical schools in SWU. SWU has in recent time experience an increase in number of medical schools distributed in various districts of the sub region. The schools included in the present study are Kampala International University (KIU), Kabale University (KU) and Mbarara University of Science and Technology (MUST) because only 3 medical schools use cadaver dissection as a method of anatomy illustration.

Cadavers in the anatomy departments of the three medical schools in SWU. Cadavers were proportionately selected from cadaver population in medical schools’ anatomy laboratories.

Using 10% proportion of total cadaver population in each medical school. A total of 25 cadavers were selected: 15 cadavers from KIU, 5 cadavers from KU and 5 cadavers from MUST.

Cadavers whose regions (axilla, groin and nasal) that had been dissected were excluded from the research study.

A checklist was used to tick what information was observed from the cadaver such as cadaver profiles and gross and microbial integrity.

The researcher and a senior anatomist from the department examined the sampled cadavers to ascertain the tissue state of the cadavers using a modified protocol adopted from Brits et al. (2020) (Table 1) [15]. Cadavers with normal fat, fascia and normal muscle tissue were said to be of good tissue quality/integrity while those with excess or thin fascia, tearing or atrophied muscle fibers and non-adherent fascia were said to be of poor tissue integrity.

For microbial surface integrity was assessed following [16] protocol with slight modifications. Swabs were collected from surface of the three regions/sites of the cadaver; axilla, nasal cavity and the female and male groin as shown in Fig. 1A–D respectively. Two swabs were collected form each site and cultured in Brain Heart Infusion Broth contained in the test tubes, after which were incubated at 37°C. Fungal cultivation was performed according to [17] with slight modification. Here, swabs were streaked directly on sabouraud dextrose agar (SDA) which were incubated at 25°C for 4–7 days. The bacterial cultures in the test tubes were later streaked on blood agar (BA) plates, violet red bile agar (VRBA) and mannitol salt agar (MSA) which were incubated at 37°C overnight [16]. Microbial identification of bacterial genera was based on colony morphology and gram staining. Fungal identification was performed by lactophenol cotton blue dye stain. Those that turned culture negative for both bacteria and fungi were said to be good Integrity as shown in Fig. 2C, D while the culture positives for either bacteria, fungi or for both were said to be of poor integrity (Fig. 2A, B).

Study tools were given a code number to identify them and once completed, they were kept in a lockable cabin where they could only be retrieved by the researcher. All data collected was double checked for errors, entered in Microsoft Excel (Microsoft) spreadsheet, cleaned, and exported to Stata version 14 (Stata Corp.) for analysis. Coding was done by allocating numbers to responses from the participants to ease analysis. All files were password protected and only availed to the researcher.

Data was analyzed using Stata version 17 (Stata Corp.), summarized into percentages, frequencies, presented in tables and figures like pie charts, bar graphs. Categorical data such as sex, level of education, culture, religion, cause of death, presence of cadaver record tag, cadavers’ sources, and race were univariately analyzed. Cadavers that have been found to be culture positive for microbes were presumed to be of poor integrity while the culture negative were presumed to be of good integrity.

Ethical approval was obtained from Bishop Stuart University Research Ethics Committee (BSU-REC) Ref No: BSU-REC-2023-161 and Uganda National Council for Science and Technology Ref No: HS3533ES. Permission to collect data from the anatomy and microbial laboratories was sought and granted by the universities’ top management. No data that easily aid tracing a cadaver in an institution was collected.

All the 25 cadavers studied in this study were of a black race with the majority 17/25 (68%) being of male sex while 8/25 (32%) cadavers were female cadavers among which only 1/8 (12.5%) was pregnant. Regarding the estimated age groups of cadavers, only 1/25 (4%) of cadavers was child while 24/25 (96%) were adults. None of the cadavers had been obtained from body donation programs thus 100% cadavers were reported to have been obtained from unclaimed bodies at the hospital. Majority (96%) of the cadavers had no cadaver record or identification tags attached yet the only 4% cadavers that had, it was incompletely filled. More than three quarters 21/25 (84%) cadavers were stored in a tank filled with embalming fluid and only brought out for dissection while 4/25 (16%) were being stored on the dissection table in cadaver bags. Dentition; 58% of the sampled cadavers had a complete/full dentition, while 8% cadavers had presence of dentures. All the cadavers were acquired when they were already preserved, they are continuous preserved using formaldehyde embalming method. We assessed for the preservation technique and found that 20% of the cadavers were preserved using only one technique (arterial embalming) while 80% were by combination of more than one embalming technique that is 72% of cadavers were preserved using both arterial embalming with surface embalming, 4% preserved using arterial, surface and cavity embalming, while 4% were by surface, cavity and hypodermic embalming (Table 2).

More than a quarter 8 (32%) of cadavers had a normal integrity of muscle fibers while 7/25 (28%) and 10/25 (40%) cadavers were tearing and atrophying respectively. Fascia integrity was normal in 16/25 (64%) cadavers while 9/25 (36%) cadavers were thin or abnormal. Less than a quarter of the cadavers had normal fat integrity while 4/25 (16%) cadavers had excess fats and 16/25 (64%) had little or no fat. Regarding dentition, 13/25 (52%) cadavers had full dentition, followed by 10/25 (40%) cadavers that had with partial dentition or were edentulous while 2/25 (8%) cadavers had dentures (Table 3).

More than a quarter 8/25 (27%) cadavers had micro-organism identified as fungi, bacteria or both on the surfaces in any of the site regions (axilla, nasal and groin) (Fig. 3). Among the cadavers that had micro-organisms present on their surfaces, 5/8 (62.5%) had both fungi and bacteria on their surfaces, 2/8 (25.0%) cadavers that had only fungi, 1/8 (12.5%) cadavers had only bacteria (Table 4).

Swabs from three sites of the 88% of micro-organisms containing cadavers showed growth on SDA with chloramphenicol thus had fungi. These culture positive samples were stained with lacto phenol blue stain and visualized using light compound microscope to identify fungi. Fungal species were identified basing on the morphological characteristics that is shape, size, aggregations of the conidiophores, length, branching of the hyphae and septations (Fig. 4) using a practical guide and atlas of fungal diagnosis. Common fungal genera were Aspergillus (23.8%), Neoscytalidium dimidiatum (19.1%), Alternaria conidae (14.3%), and Scopularis (4.8%) (Table 5).

Samples that were culture positive on MSA, BA, and VRBA were differentiated using gram staining technique into the gram positive and gram-negative bacteria. Of the micro-organisms containing cadavers, 75% of the cadavers contained bacteria on their surface with the majority (61%) being gram positive bacteria while gram negative bacteria formed (39%) (Table 6). These were further classified basing on shape, appearance in single, chain or clusters and the majority was Staphylococcus, followed by Streptococcus, Bacillus and Streptobacillus (Fig. 5).

Our study found that all the cadavers were of black race with non from white or the colored race. Our results are in agreement with studies among universities in Kenya [18], Tanzania [19], and Nigeria [20] where all the cadavers dissected were of black race. This could be because SWU, Kenya, Tanzania, and Nigeria are largely inhabited by blacks with less or no white population. Our study however is in disagreement with studies conducted in South African, where cadavers used in dissection were of mixed race with the majority from a white race than black and colored race [21]. In the university of cape town South Africa, the cadaver collections by 2016 constituted majority (70%) being of white race [22], while in University of Stellenbosch in South Africa, majority (62.6%) of cadavers were of colored race followed white race (22.1%) and lastly black race (15.3%) [23]. This could be attributed to South Africa being a multi-racial nation equally inhabited by the both the blacks, whites and colored population races [21]. By 2020, all the cadavers dissected in University of the Witwatersrand, Johannesburg were of white race [15]. This also could be attribute to unwillingness of blacks to self-body donation. The present study reports racial homogeneity in cadaver populations instead of multiracial population. This homogeneity in cadaver racial population risks to long-term effect in anatomical studies and medical practice.

Our study reveals that majority (68%) of cadavers were of male sex. This study agrees with other studies conducted in Tanzanian universities and Nigeria where 94% and 92.7% of cadavers dissected in 5 years were are male [19, 20]. This could be attributed to high and early death rates of men in developing countries but also due to the fact that women attribute more to their religious and cultural beliefs which restrict them to donate their bodies or leave them unclaimed [24, 25]. Even in middle and developed countries like South Africa, India, and United States which acquire cadavers through body donation programs, various studies conducted in medical schools also confirm that male cadavers predominate the dissection laboratories [21-23]. This could be attributed to low levels willingness to self-cadaver donation among women than men as also seen from our study finding where men (72%) were more willing than women (28%). Important to note is that the number of female cadavers is drastically decreasing reported by Mazyala et al. [19], 2014 study where female cadavers decreased from 19.6% to 6% in period of 3 years. Cadaver population of one sex affects the teaching and learning of anatomy in a way it denies the learners a chance to appreciate anatomy of female reproductive system, pelvis and special anatomy-clinical conditions like pregnancy.

In our study, majority (96%) of cadavers had no cadaver record tag and even the 4% cadavers that had the records were incompletely filled. This could be due to lack of cadavers are obtained from non-recommended sources and due to lack of donation policy and programs that would guide, require a clear and proper documentation for a cadaver before acquisition. Our study findings are in agreement with findings from a South African study where a total of 933 cadavers had partially filled records [21]. In a similar study among medical schools in Tanzania, all the cadavers had record but all the record had missing information [19]. However, the present study contradicts with findings reported by Popoola et al. [20] where all the 41 cadavers in anatomy departments had record information both in the cadaver registry and cadaver record tag. Additionally, studies in South Africa, American medical schools have also reported all the cadavers having cadaver record tags with filled. This could be attributed to the presence of strong policies and strong emphasis put on records while procuring cadavers in their medical schools. Cadaver record tags are vital because they provide information about the cadaver that will aid in the further handling of the cadaver. For example, in our study, majority (96%) cadavers had unknown cause of death except for only 4% cadavers that was due to accident and trauma. This is because majority (96%) cadavers with unknown cause of death had no cadaver record tag while 4% cadavers with known cause of death, the information was obtained from cadaver tag. Therefore, medical schools should accurately collect and keep records as they not only aid on the right handling of cadavers but provide information that might be further used in research.

Regarding sources of cadavers, all the cadavers in our study were from unclaimed bodies from the health facilities with none from body donation programs. This could be attributed to the fact that there are no body donation programs in medical schools in SWU and no cadaver donation policy in Uganda. Our study findings concur with findings published by [18, 19] where all cadavers used in Tanzania and Kenyan universities were from the unclaimed sources. Similar finding have also been in most of African medical schools with an exception of Libya where the bodies used were imported from India [14, 21]. This is because, like Ugandan medical schools, African medical schools lack body donation programs and policies in nations they are located. However, in Nigerian universities, despite having body donation policies and programs, none of the dissected cadavers were from the body bequest program [20, 26]. The present study is in disagreement with studies conducted in South Africa, United States, United Kingdom, and Europe where majority of the cadavers dissected in their medical schools are from body donation program [8, 14]. This is because, there are cadaver donation programs in their medical schools and strong body donation policy in these countries. Medical schools which have implemented body donation programs include wit waters Rand University, universities of Cape Town, and Stellenbosch in South Africa [15, 22], Nottingham University in the United States, and River state in Nigeria among others. They mentioned schools and regions have adhered to body donation policies and document every information on a cadaver [20]. This can also be achieved in SWU only if there is a strong enacted body donation policy strongly enforced implementing bodies like ministry of education, national councils of higher education, Ministry of Health and Anatomical Association of Uganda. Cadavers obtained from non-donation sources like grave robberies, victims of war, importing of cadavers, human trafficking, unclaimed bodies are not of good gross tissue quality and microbial quality integrity for dissection in the laboratory hall and are not recommended by the IFAA [6-8]. For example, cadavers obtained from grave robberies would have started decomposing at the time of acquisition, trafficked cadavers may not have been screened for infectious agents while the bandits/victims of war have distorted or missing gross parts thus poor gross and microbial integrity of cadavers making them unfit for dissection [9, 10]. African countries especially those having a rapid increase in the number of medical teaching schools like Uganda should enact the body donation policy and establish body donation programs in their medical schools.

Our study examined the gross tissue integrity of the cadavers in regards dentition, the quantity and quality of fascia, fat beneath the skin of the cadavers and the strength, intactness of the muscle fibers of the cadaver. More than a half (52%) of the cadavers had full dentition, followed by 40% cadavers that had with partial dentition or were edentulous while 8% cadavers had dentures present (Table 3). This study concurs with a South African study that showed that majority (51%) of the population of cadavers had complete set of dentition while 29% cadavers edentulous [15]. Another case was reported in South Africa where up to 72 of 343 cadaveric individuals were missing some elements [22]. This finding could be attributed to the source of cadavers as from war victims/bandits, prison dead victims who could have faced torture during investigation or unclaimed bodies from health facility who could have been victims of accidents, or the bodies were not screened for dentition at the time of acquisition. Missing parts of cadavers affect learning by denying students the chance to appreciate some anatomical features like the dental medicine students would be in respect to this case [21]. For example, various studies have revealed that cadavers and murder victims could be person identified by studying the teeth, bones and other body parts [27, 28]. It is thus vital to always screen and obtain cadavers with complete dentition or other parts so that student may not miss out.

On fat integrity, our study found out that, only 20% cadavers had normal fat integrity while 64% had no fat and 16% had excess fat tissue below the skin. More so, more than a half (36%) of the sampled cadavers had very thin fascia while 64% had normal adhering fascia (Table 3). This agrees with a study in University of the Witwatersrand, Johannesburg reported that 33% cadavers had normal fat, 33% cadavers had excess while 33% cadavers had no fat. About 60% had adhering fascia, 33% with thin and 7% with thick fascia [15]. In another study, 30.7% cadavers had excess superficial subplatysmal fat while no fat 1% in deep compartment of the neck [29]. Normal fat is important anatomical feature but cadavers with excess or no fat are not good for anatomical teaching and learning. For example, fat in dissection is seen as an obstacle to access deep structures during dissection [29]. Obese cadavers become heavy after embalming with fluids, take up a lot of storage space, and even when dissected, learners can’t clearly appreciate structures since there is fat tissue everywhere [30]. But fat also has its good contribution to medical practice, anatomy teaching and learning. It actually offers more than just body for dissection, by giving us insights on bodies’ subjectivity, scientific order [31]. For instance, fat is utilized in different studies such as body mass index estimate [32, 33], in clinical trials for drugs like insulin resistance and testing for effectiveness of some investigative techniques like magnetic resonance imaging against normal dissection/physical exam palpation which are vital in patient management [34, 35]. It also acts as a landmark of structures of interest during some surgical operations thus guiding surgeons in surgical approaches. Obese cadavers have an attitude and perception change effect on learners on dissection and body donation [29]. In developing countries where body bequest programs are still underdeveloped, obese bodies are accepted while in countries with developed bequest program, obese bodies have been turned down because they don’t meet the recruitment criteria [30]. It’s thus important that medical schools while acquiring cadavers to weigh between the intended purposes of the cadavers and procure fatty, normal or no fat cadavers accordingly. Fat levels in cadavers affect the way medical students perceive and learn anatomy. For example, medical students in the United States reported that fatty cadavers were difficult, unhealthy and evoke disgust to dissect [29]. This extrapolated perception from dissecting fatty cadavers affects their future interactions with fat patients. Efforts to reduce fat/weight bias should be set in place to enable effective learning of anatomy. This could be one of the body donation criteria where fatty/obese cadavers could not be accepted to be donated.

The present study reports that 8/25 (32%) cadavers had a normal muscle integrity, 10/25 (40%) cadavers had atrophying muscles while 28% had tearing muscle fibers in our study (Table 3). This concurs with finding from a study done in South Africa where 78% cadavers had muscle fibers atrophying, while 84% had muscle fibers that were tearing while 76% were both tearing and atrophying [15]. The observation in the present study could be attributed to the type of embalming fluids and methods used to preserve the cadavers. Formaldehyde based solutions have been associated with hardening/stiffening and atrophying muscle fibers while Thiel embalming solution has been linked to softening/flexibility but tearing muscle fibers [36]. Additionally, these preservation methods are not 100% at eliminating microbes on cadaver surface which might decompose the muscle fibers leading to their tearing thus poor muscle fiber integrity [37]. Poor muscle integrity of cadavers affects students learning of gross aspects of muscles and tendons like origin and insertion, size and orientation and histological context of muscles fibers [38]. Therefore, medical schools while procuring cadavers should always strive hard to acquire cadavers with or preserve the normal muscle tissue integrity for better learning experience for students.

In this study, more than a quarter (27%) cadavers had micro-organisms on the surfaces from any of the three regions (axilla, nasal and groin). Most cadavers containing microorganism contain a mixture of fungi and bacteria on their surfaces (62.5%), 25.0% cadavers had only fungi while 12.5% had bacteria only. This could be attributed to poor preservation methods such as poorly diluted formalin solution or students introducing microbes on their laboratory coats to the cadavers. Our study is in consensus with findings reported by [16, 39], where all cadavers and organ/tissues sections studied had microbes on their surfaces with the majority inhabited by bacteria. Similar findings were reported in studies in Indian medical schools where 78% samples from deep and superficial cadaver surfaces were culture positive for bacteria and fungi where the majority were bacterial (50%), followed by fungi (30.76%) and then mixture of bacteria and fungi (19.23%) [40]. Moreover, these cadavers, organ/tissue sections are preserved (disinfected and fixed) using 10% formalin solution or 37% formaldehyde solution which are tested, trusted and mostly used fixatives and disinfectants against the bacteria and fungi on cadavers [37]. This could be attribute this to the fact that students/dissectors introduce these microbes to sterile cadavers during dissection thus infecting them. This was evidenced when 55 bacterial isolates obtained from 120 samples taken from students’ gloves after dissection [16]. This shows that in a poorly preserved or infection exposed cadavers, micro-organisms will likely grow on even if the cadavers were initially sterile. The present study reveals that, 69% of bacteria cultured were gram positives while 31% were gram negatives. Among the fungi, Aspergillus consisted the majority (24%), followed by Neoscytalidium dimidiatum (20%), Alternaria (16%) (Table 4). This finding is contrary to [39] where the majority (85.7%) bacteria were gram negatives while 14.3% were gram positive bacteria. In study, 30.76% microbes growing on human cadavers were purely fungi among which Aspergillus species (37.50%) being the most dominant followed by Candida species (25%) and then other species [40]. This could because of different micro-organisms found in different countries and poor dilution of embalming fluid/reduction in active component concentration in embalming fluid, inadequate/poor embalming technique or micro-organisms in different localities are becoming resistant to the embalming fluids [41]. Formaldehyde based embalming solutions has been reported to be ineffective at disinfecting cadavers and being carcinogenic poses it as an occupational hazard to laboratory technicians, anatomy illustrators and students [37, 42]. Other methods of cadaver preservation like Phosphate-buffered saline, Thiel embalming, ortho-phthalaldehyde (0.55%), ultraviolet (UV) irradiation of cadavers have been proposed and shown promising results [37, 43, 44]. A combination of formalin/formaldehyde embalming, and UV radiation exposure could produce microbial free cadavers. The presence of microprisms on the surface of cadavers causes decomposition of cadaver tissues like muscle fibers, fascia and internal organs thus destroying the gross tissue integrity of cadavers and affecting learning. This highlights the need for medical schools to ensure proper and regular preservation methods and store cadavers well to reduce the risk of microbial growth on cadavers. It’s vital to note that cadavers to be used for dissection should be screened for microbes and be microbe free. Medical schools should always carefully screen and adequately preserve cadavers in during the cadaver procuring process.

The quality of cadavers being dissected affects the quality of anatomy learning and outcomes of medical, surgical, forensic and archeological practice [45, 46]. Cadavers with microbes on their surfaces are unsafe for student learning as they pose a high risk of infection transmission to students which consequently can be transmitted to the societies’ students reside in [16, 40]. Moreover, these microbes have developed resistance to formalin thus may spread antimicrobial resistance to other antimicrobial agents being used to treat infections in the community [37, 41, 47]. Additionally, these microbes cause decomposition of cadaver tissues which increases the rate of cadaver usage which in turn reduces the availability of cadavers for dissection in medical schools [48]. More so, decomposed tissues most especially soft tissues like fascia, the heart, lungs and other visceral organs to have acquaintance of rare structures and clinical skills [36, 49]. For example, absence or decomposition of female reproductive organs on a cadaver would interfere with the learner’s ability to appreciate structures in female reproductive cycle events like pregnancy [50, 51]. This greatly impacts on medical education as medical students will have poor physical examination and surgical skills. Understanding of gross tissue integrity like dentition would aid dental students to appreciate the pathologies of altered dentition [27]. Dental carries and tooth extracted before death or congenital absence of the teeth can be examined in cadaver [27]. More so studies show that dentition could be used to trace and identify cadavers of specific individuals [27]. Missing dentition could limit this application while teaching forensic medicine to medical students. On the other hand, altered dentition in like missing teeth could aid also to predict the cause of death such as trauma or head injuries [28].

Information on cause of death is used to identify and demonstrate the disease effect on particular organ. For example, knowing the person died due to lung tuberculosis or liver cirrhosis with hepatosplenomegaly would aid the instructor to isolate the diseased lungs, enlarged liver and spleen respectively and use them to demonstrate to students [15]. Information about the cause of death can help the instructors to create a safe working and learning environment for the instructors and learners respectively. For example, a body whose cause of death was ebola or corona virus disease 2019 could not be dissected as it risks transmission to students [16, 40]. This signals the laboratory technicians, dissection instructors and the medical school management to implement serious infectious disease measures thus creating a safe working and learning environment for instructors and students respectively. Further studies to determine the integrity of cadavers in other regions of the country and also to determine the antimicrobial resistance patterns of microbes on cadavers should be conducted.

The present study was conducted in anatomy laboratories of only three medical schools in one sub region which can limit the generalizability to all medical schools in the whole Uganda. This study was unable to conduct antimicrobial resistance patterns of the isolated micro-organisms from cadaver surfaces.

As at the time of the present publications, schools in SWU are beginning make efforts to ensure their cadavers and laboratories are in the right state following the outcome of the present study. This is a landmark achievement that cannot be taken for granted.

In conclusion, majority of the cadavers blacks, male, adults, formalin embalmed, no cadaver record tag, unknown cause of death, and from unclaimed body sources. Majority of cadavers had poor gross tissue integrity mostly affecting the dentition and muscle fibers. Cadavers in medical schools contained micro-organisms on their surfaces with the majority having a mixture of both bacteria and fungi despite their embalming with 10% formalin preservation solution.